Protein structure analysis of mutations causing inheritable diseases. An e-Science approach with life scientist friendly interfaces. BMC Bioinformatics. 2010;11:548. [PMID: 21059217 PMCID: PMC2992548 DOI: 10.1186/1471-2105-11-548]

Deciphering the genetic impact of signal peptide missense CTLA-4 polymorphism with rheumatoid arthritis in the Indian population: A case-control and in silico studies

Cytoplasmic T Lymphocyte Antigen-4 (CTLA-4) gene encodes for a glycoprotein, expressed on activated T-cells to transfer an inhibitory signal to control T-cell activation and proliferation. Techniques coupled with Real-time Polymerase Chain Reaction (PCR) and High-Resolution Melting Analysis (HRMA) were used to screen a missense signal peptide polymorphism (CTLA-4 + 49 A/G rs231775) in the Indian population to detect its association with Rheumatoid Arthritis (RA). Further, the resulting outcome was confirmed by Sanger's sequencing technique, and genotype frequencies were calculated. In eukaryotic cells, the M domain of the Signal Recognition Particle (SRP-54) recognizes the N-terminal region of the Signal Peptide (SP) sequence. SP directs the polypeptide chain into the Sec-61 translocon of the Endoplasmic Reticulum (ER) for further protein modification. As the Single Nucleotide Polymorphism (SNP) rs231775 lies in the signal peptide region of CTLA-4, an in-silico study was also performed to predict the mRNA stability and SP-SRP protein interaction. From the study, it was observed that the genotype frequency of rs231775 SNP G/G homozygous dominant was significantly higher in RA patients than G/A heterozygous dominant and A/A homozygous recessive conditions (Odd Ratio (OR) = 2.0862; 95 % Confidence Interval (C.I) = 1.2584 to 3.4584; Relative Risk (RR) = 1.8507; p = 0.0044). Moreover, the rs231775 SNP G allele frequency was higher in RA than the control group G = 0.407 (40.7 %) vs 0.32 (32 %). In silico approaches of Protein-Protein docking and Molecular Dynamics (MD) simulation reveal CTLA-4 rs231775 SNP (G allele) has destabilized the SP-SRP protein complex, which may affect the translocation of CTLA-4 nascent polypeptide chains into the ER via activating Regulation of Aberrant Protein Production (RAPP) pathway.

CDKN1C -Related Beckwith-Wiedemann Syndrome: First Patient from India

Beckwith-Wiedemann syndrome (BWS; MIM# 130650) is a well-characterized pediatric overgrowth disorder. In approximately 5% of the cases, it is caused by pathogenic variants in the CDKN1C (cyclin-dependent kinase inhibitor 1C). CDKN1C gene encodes for a protein p57 (KIP2) that acts as an inhibitor of cyclin-dependent kinases (CDK) that are expressed in the G and S-phase of the cell cycle, thus regulating cellular proliferation. Variants in CDKN1C gene lead to loss of inhibitory function of CDK and thus impair the inhibition of growth, resulting in BWS phenotype. We describe here a 2.5-year-old boy with a maternally inherited variant c.182G > T, p.Trp61Cys in the CDKN1C gene causing BWS. The natural history of the disorder is described along with the gradual change in the facial features. An insight into the genotype-phenotype correlation and disorders to be considered in the differential diagnosis is provided. We describe a common overgrowth syndrome with its rare genetic mechanism and highlight the salient features that help in making a diagnosis and managing patients.

Novel variants in DNAH9 are present in two infertile patients with severe asthenospermia

Asthenospermia is a type of sperm that has malformed sperm with movement disorders that lead to male infertility. DNAH9 is a member of the dynein family and a central part of the outer dynein arm of cilia and flagella. DNAH9 gene defects are associated with primary ciliary dyskinesia and ultrastructural abnormalities in ciliary axial ultrastructure. However, the role of DNAH9 in sperm motility remains unclear, prompting us to investigate its function in spermatozoa. Familial Sanger sequencing showed that sterile males carried homozygous DNAH9 variants (c. 12218A>C, p. N4073T) and compound heterozygous variants (c.8617G>A, p.V2873M; c.11742A>T, p.E3914D), respectively. Transmission electron microscopy revealed these variants resulted in a significant lack of outer dynein arms in the cross-sectional view of the axoneme in both patients. Immunofluorescence results showed that these variants can lead to decline in DNAH9 protein expression, which led to the dysfunction of flagellar ultrastructure-related proteins, including DNAI1, DNAH1 and DNAH10. In conclusion, we identified novel biallelic variants in DNAH9 that likely bring about sharply decreased motility of spermatozoa in the two patients with asthenospermia. Our findings will widen the variant spectrum of known DNAH9 variants involving asthenospermia and further offer more proofs for genetic counseling and diagnosis.

A Novel NRAS Variant Near the Splice Junction in Moroccan Childhood Acute Lymphoblastic Leukemia: A Molecular Dynamics Study

The RAS genes are importantly implicated in oncogenesis and are frequently mutated in childhood acute lymphoblastic leukemia. This study is the first to our knowledge, to determine the mutational status of NRAS and KRAS genes in Moroccan pediatric acute lymphoblastic leukemia (ALL). Polymerase chain reaction and Sanger sequencing were performed for 45 ALL samples to explore the coding exons. The functional effect of the mutation was evaluated using in silico prediction tools and molecular modeling. We identified a novel variant c.290 G > C p.Arg97Thr within NRAS gene in a patient with T-ALL, which is a rare missense point mutation affecting the last base of exon 3. Analyses revealed that p.Arg97Thr impairs the adjacent splice site efficiency. Moreover, it leads to structural modifications at local and global levels of the protein through the loss of hydrogen bonds. Additionally, the molecular dynamics (MD) simulation showed that it slightly increases the stability of NRAS protein by locally decreasing the flexibility of the mutated region. No variant was detected within KRAS gene. R97 at NRAS gene is an overlapping splice site residue. Our findings suggest that the NRAS p.Arg97Thr variant may disrupt the splicing machinery and functions of the protein, thus playing a vital role in leukemogenesis. In addition, the highly druggable pocket may possibly be studied for its therapeutic implications.

Genetic and functional analyses of CTBP2 in anorexia nervosa and body weight regulation

The C-terminal binding protein 2 (CTBP2) gene (translational isoforms: CTBP2-L/S, RIBEYE) had been identified by a cross-trait analysis of genome-wide association studies for anorexia nervosa (AN) and body mass index (BMI). Here, we did a mutation analysis in CTBP2 by performing polymerase chain reactions with subsequent Sanger-sequencing to identify variants relevant for AN and body weight regulation and ensued functional studies. Analysis of the coding regions of CTBP2 in 462 female patients with AN (acute or recovered), 490 children and adolescents with severe obesity, 445 healthy-lean adult individuals and 168 healthy adult individuals with normal body weight detected 24 variants located in the specific exon of RIBEYE. In the initial analysis, three of these were rare non-synonymous variants (NSVs) detected heterozygously in patients with AN (p.Arg72Trp - rs146900874; p.Val289Met -rs375685611 and p.Gly362Arg - rs202010294). Four NSVs and one heterozygous frameshift variant were exclusively detected in children and adolescents with severe obesity (p.Pro53Ser - rs150867595; p.Gln175ArgfsTer45 - rs141864737; p.Leu310Val - rs769811964; p.Pro397Ala - rs76134089 and p.Pro402Ser - rs113477585). Ribeye mRNA was detected in mouse hypothalamus. No effect of fasting or overfeeding on murine hypothalamic Ribeye expression was determined. Yet, increased Ribeye expression was detected in hypothalami of leptin-treated Lepob/ob mice. This increase was not related to reduced food intake and leptin-induced weight loss. We detected rare and frequent variants in the RIBEYE specific exon in both patients with AN and in children and adolescents with severe obesity. Our data suggest RIBEYE as a relevant gene for weight regulation.

Investigating the role of non-synonymous variant D67N of ADGRE2 in chronic myeloid leukemia

BACKGROUND

Chronic myeloid leukaemia (CML) is a type of blood cancer that begins in the hematopoietic stem cells. It is primarily characterized by a specific chromosomal aberration, the Philadelphia chromosome. While the fusion gene is a major contributor to CML, several other genes including ADGRE2, that are reported as highly expressed in hematopoietic stem cells and could be utilized as a therapeutic marker in leukemic patients are implicated in the disease's progression. Until recently, little research had been conducted to identify single nucleotide polymorphisms (SNPs) associated with CML. Therefore, this study aims to investigate the influence of non-synonymous variants on the structure and function of the gene encoding adhesion G protein-coupled receptor E2, ADGRE2, and to evaluate their association with CML and its clinical and pathological characteristics.

METHODS

Non-synonymous SNPs of ADGRE2 were retrieved from the ENSEMBL, COSMIC, and gnomAD genome browsers, and the pathogenicity of deleterious variants was assessed using several established computational tools, including SIFT, CADD, REVEL, PolyPhen, and MetaLR.

RESULTS

Various in silico analyses explored the impact of damaging SNP on the function, stability, and structure of EGF-like modules containing mucin-like hormone receptor-like2 (EMR2) protein encoded by the ADGRE2 gene. Genotype analysis was performed on collected blood samples, revealing that altered genotype TT of variant rs765071211 (C/T) was associated significantly with CML patients compared to the control. Further in vitro and in vivo analyses suggest that this SNP holds potential for clinical translation.

Investigation of patients with childhood epilepsy in single center: Comprehensive genetic testing experience

INTRODUCTION

Epilepsy is a common multifactorial neurological disease usually diagnosed during childhood. In this study, we present the contribution of consecutive genetic testing to the genetic diagnostic yield of childhood epilepsy.

METHODS

In 100 children (53 female, 47 male) with epilepsy, targeted sequencing (TS) and clinical exome sequencing (CES) were performed. All cases (n = 100) included in the study were epilepsy patients. In addition, we investigated the genetic diagnosis rates according to the associated co-occurring findings (including developmental delay/intellectual disability, brain malformations, macro-/microcephaly, and dysmorphic features).

RESULTS

The overall diagnostic rate in this study was 33% (n = 33 patients). We identified 11 novel variants in WDR45, ARX, PCDH19, SCN1A, CACNA1A, LGI1, ASPM, MECP2, NF1, TSC2, and CDK13. Genetic diagnosis rates were as follows: cases with developmental delay/intellectual disability 38.7% (24/62) and without developmental delay/intellectual disability 23.6% (9/38); cases with brain malformations 46.8% (15/32) and without brain malformations 25% (16/64); cases with macro-/microcephaly 50% (6/12) and without macro-/microcephaly 28.4% (25/88); and cases with dysmorphic features 48.2% (14/29) and without dysmorphic features 23.9% (17/71).

CONCLUSION

Genotype-phenotype correlation is even more important in diseases such as epilepsy, which include many genes and variants of these genes in etiopathogenesis. We presented the clinical findings of the cases carrying 11 novel variants in detail, including dysmorphic features, accompanying neurodevelopmental disorders, EEG results, and brain MRI results.

Another face of RASA1: Report of familial germline variant in RASA1 with dysmorphic features

RASopathies encompass a diverse set of disorders affecting genes that encode proteins within the RAS-MAPK pathway. RASA1 mutations are the cause of an autosomal dominant disorder called capillary malformation-arteriovenous malformation type 1 (CM-AVM1). Unlike other RASopathies, facial dysmorphism has not been described in these patients. We phenotypically delineated a large family of individuals with multifocal fast-flow capillary malformations, severe lymphatic anomalies of perinatal onset, and dysmorphic features not previously described. Sequencing studies were performed on probands and related family members, confirming the segregation of dysmorphic features in affected members of a novel heterozygous variant in RASA1 (NM_002890.3:c.2366G>A, p.(Arg789Gln)). In this work, we broaden the phenotypic spectrum of CM-AVM type 1 and propose a new RASA1 variant as likely pathogenic.

Increased Prevalence of Germline Pathogenic CHEK2 Variants in Individuals With Pituitary Adenomas

CONTEXT

CHEK2 is a cell cycle checkpoint regulator gene with a long-established role as a clinically relevant, moderate risk breast cancer predisposition gene, with greater risk ascribed to truncating variants than missense variants.

OBJECTIVE

To assess the rate and pathogenicity of CHEK2 variants amongst individuals with pituitary adenomas (PAs).

METHODS

We assessed 165 individuals with PAs for CHEK2 variants. The study population comprised a primary cohort of 29 individuals who underwent germline and tumor whole-exome sequencing, and a second, independent cohort of 136 individuals who had a targeted next-generation sequencing panel performed on both germline and tumor DNA (n = 52) or germline DNA alone (n = 84).

RESULTS

We identified rare, coding, nonsynonymous germline CHEK2 variants amongst 3 of 29 (10.3%) patients in our primary cohort, and in 5 of 165 (3.0%) patients overall, with affected patients having a range of PA types (prolactinoma, thyrotropinoma, somatotropinoma, and nonfunctioning PA). No somatic variants were identified. Two variants were definitive null variants (c.1100delC, c.444 + 1G > A), classified as pathogenic. Two variants were missense variants (p.Asn186His, p.Thr476Met), classified as likely pathogenic. Even when considering the null variants only, the rate of CHEK2 variants was higher in our cohort compared to national control data (1.8% vs 0.5%; P = .049).

CONCLUSION

This is the first study to suggest a role for the breast cancer predisposition gene, CHEK2, in pituitary tumorigenesis, with pathogenic/likely pathogenic variants found in 3% of patients with PAs. As PAs are relatively common and typically lack classic autosomal dominant family histories, risk alleles-such as these variants found in CHEK2-might be a significant contributor to PA risk in the general population.

Bioinformatic Characterization of the Functional and Structural Effect of Single Nucleotide Mutations in Patients with High-Grade Glioma

Background: Gliomas are neoplasms of the central nervous system that originate in glial cells. The genetic characteristics of this type of neoplasm are the loss of function of tumor suppressor genes such as TP53 and somatic mutations in genes such as IDH1/2. Additionally, in clinical cases, de novo single nucleotide polymorphisms (SNP) are reported, of which their pathogenicity and their effects on the function and stability of the protein are known. Methodology: Non-synonymous SNPs were analyzed for their structural and functional effect on proteins using a set of bioinformatics tools such as SIFT, PolyPhen-2, PhD-SNP, I-Mutant 3.0, MUpro, and mutation3D. A structural comparison between normal and mutated residues for disease-associated coding SNPs was performed using TM-aling and the SWISS MODEL. Results: A total of 13 SNPs were obtained for the TP53 gene, 1 SNP for IDH1, and 1 for IDH2, which would be functionally detrimental and associated with disease. Additionally, these changes compromise the structure and function of the protein; the A161S SNP for TP53 that has not been reported in any databases was classified as detrimental. Conclusions: All non-synonymous SNPs reported for TP53 were in the region of the deoxyribonucleic acid (DNA) binding domain and had a great impact on the function and stability of the protein. In addition, the two polymorphisms detected in IDH1 and IDH2 genes compromise the structure and activity of the protein. Both genes are related to the development of high-grade gliomas. All the data obtained in this study must be validated through experimental approaches.

The clinical and genetic aspects of six individuals with GH1 variants and isolated growth hormone deficiency type II

Background

Isolated growth hormone deficiency type II (IGHD II) is an autosomal dominant disorder characterized by a GH1 gene variant resulting in a significant reduction in growth hormone (GH) secretion and a subsequent decrease of plasma insulin-like growth factor 1 (IGF-1) levels and eventual growth impairment.

Objective

This study aimed to identify causative variants in six Chinese families with IGHD II, exploring both clinical and genetic characteristics.

Methods

Detailed clinical data, including clinical presentations, physical charateristics, medical and family histories, as well as genetic test results, were systematically examined.

Results

Six children, comprising four males and two females, with a mean age of 4.64 ± 1.15 years, exhibited short stature with a mean height of -3.95 ± 1.41 SDS. Four of them had a family history of short stature, while one patient presented with pulmonary hypertension. All children demonstrated GH deficiency in growth hormone stimulation tests (mean peak GH value: 2.83 ± 2.46 ng/mL). Exome sequencing for the six patients and targeted gene sequencing for their family members revealed heterozygous variants in the GH1 gene, including Exon2-5del, c.334T>C, c.291 + 1G>A, c.291 + 2T>A, 1.5 kb deletion, and 1.7 kb deletion, with four variants being novel. Four patients underwent human recombinant growth hormone (rhGH) replacement therapy, initiating treatment at a mean age of 4.6 ± 0.7 years. The mean height increase in patients was 1.21 ± 0.3 SDS in the first six months of treatment and 1.79 ± 0.15 SDS in the first year.

Conclusion

Our findings contribute to expanding the genotypic and phenotypic spectra of individuals with IGHD II.

Identification of Pathogenic Missense Mutations of NF1 Using Computational Approaches

Neurofibromatosis type 1 (NF1) is a prevalent autosomal dominant disorder caused by mutations in the NF1 gene, leading to multisystem disorders. Given the critical role of cysteine residues in protein stability and function, we aimed to identify key NF1 mutations affecting cysteine residues that significantly contribute to neurofibromatosis pathology. To identify the most critical mutations in the NF1 gene that contribute to the pathology of neurofibromatosis, we employed a sophisticated computational pipeline specifically designed to detect significant mutations affecting the NF1 gene. Our approach involved an exhaustive search of databases such as the Human Gene Mutation Database (HGMD), UniProt, and ClinVar for information on missense mutations associated with NF1. Our search yielded a total of 204 unique cysteine missense mutations. We then employed in silico prediction tools, including PredictSNP, iStable, and Align GVGD, to assess the impact of these mutations. Among the mutations, C379R, R1000C, and C1016Y stood out due to their deleterious effects on the biophysical properties of the neurofibromin protein, significantly destabilizing its structure. These mutations were subjected to further phenotyping analysis using SNPeffect 4.0, which predicted disturbances in the protein's chaperone binding sites and overall structural stability. Furthermore, to directly visualize the impact of these mutations on protein structure, we utilized AlphaFold3 to simulate both the wild-type and mutant NF1 structures, revealing the significant effects of the R1000C mutation on the protein's conformation. In conclusion, the identification of these mutations can play a pivotal role in advancing the field of precision medicine and aid in the development of effective drugs for associated diseases.

Clinical and Molecular Profiles of a Cohort of Egyptian Patients with Collagen VI-Related Dystrophy

Collagen VI-related dystrophies (COL6-RD) display a wide spectrum of disease severity and genetic variability ranging from mild Bethlem myopathy (BM) to severe Ullrich congenital muscular dystrophy (UCMD) and the intermediate severities in between with dual modes of inheritance, dominant and recessive. In the current study, next-generation sequencing demonstrated potential variants in the genes coding for the three alpha chains of collagen VI (COL6A1, COL6A2, or COL6A3) in a cohort of Egyptian patients with progressive muscle weakness (n = 23). Based on the age of disease onset and the patient clinical course, subjects were diagnosed as follows: 12 with UCMD, 8 with BM, and 3 with intermediate disease form. Fourteen pathogenic variants, including 5 novel alterations, were reported in the enrolled subjects. They included 3 missense, 3 frameshift, and 6 splicing variants in 4, 3, and 6 families, respectively. In addition, a nonsense variant in a single family and an inframe variant in 3 different families were also detected. Recessive and dominant modes of inheritance were recorded in 9 and 8 families, respectively. According to ACMG guidelines, variants were classified as pathogenic (n = 7), likely pathogenic (n = 4), or VUS (n = 3) with significant pathogenic potential. To our knowledge, the study provided the first report of the clinical and genetic findings of a cohort of Egyptian patients with collagen VI deficiency. Inter- and intra-familial clinical variability was evident among the study cohort.

CFTR Exon 10 deleterious mutations in patients with congenital bilateral absence of vas deferens in a cohort of Pakistani patients

Congenital bilateral absence of vas deferens (CBAVD) is a urological syndrome of Wolffian ducts and is responsible for male infertility and obstructive azoospermia. This study is designed to explore the integrity of exon 10 of CFTR and its role in male infertility in a cohort of CBVAD patients in Pakistan. Genomic DNA was extracted from 17 male patients with CBAVD having clinical symptoms, and 10 healthy controls via phenol-chloroform method. Exon 10 of the CFTR gene was amplified, using PCR with specific primers and DNA screening was done by Sanger sequencing. Sequencing results were analyzed using freeware Serial Cloner, SnapGene, BioEdit and FinchTV. Furthermore, bioinformatics tools were used to analyze the mutations and their impact on the protein function and stability. We have identified 4 mutations on exon 10 of CFTR in 6 out of 17 patients. Two of the mutations were missense variants V456A, K464E, and the other two were silent mutations G437G, S431S. The identified variant V456A was present in 4 of the studied patients. Whereas, the presence of K464E in our patients further weighs on the crucial importance for its strategic location to influence the gene function at post-transcriptional and protein level. Furthermore, Polyphen-2 and SIFT analyze the mutations as harmful and deleterious. The recurrence of V456A and tactically conserved locality of K464E are evidence of their potential role in CBAVD patients and in male infertility. The data can contribute in developing genetic testing and treatment of CBAVD.

Unlocking the Door for Precision Medicine in Rare Conditions: Structural and Functional Consequences of Missense ACVR1 Variants

Rare diseases and conditions have thus far received relatively less attention in the field of precision/personalized medicine than common chronic diseases. There is a dire need for orphan drug discovery and therapeutics in ways that are informed by the precision/personalized medicine scholarship. Moreover, people with rare conditions, when considered collectively across diseases worldwide, impact many communities. In this overarching context, Activin A Receptor Type 1 (ACVR1) is a transmembrane kinase from the transforming growth factor-β superfamily and plays a critical role in modulating the bone morphogenetic protein signaling. Missense variants of the ACVR1 gene result in modifications in structure and function and, by extension, abnormalities and have been predominantly linked with two rare conditions: fibrodysplasia ossificans progressiva and diffuse intrinsic pontine glioma. We report here an extensive bioinformatic analyses assessing the pool of 50,951 variants and forecast seven highly destabilizing mutations (R206H, G356D, R258S, G328W, G328E, R375P, and R202I) that can significantly alter the structure and function of the native protein. Protein-protein interaction and ConSurf analyses revealed the crucial interactions and localization of highly deleterious mutations in highly conserved domains that may impact the binding and functioning of the protein. cBioPortal, CanSAR Black, and existing literature affirmed the association of these destabilizing mutations with posterior fossa ependymoma, uterine corpus carcinoma, and pediatric brain cancer. The current findings suggest these deleterious nonsynonymous single nucleotide polymorphisms as potential candidates for future functional annotations and validations associated with rare conditions, further aiding the development of precision medicine in rare diseases.

Genetic profile of progressive myoclonic epilepsy in Mali reveals novel findings

Background and objectives

Progressive myoclonic epilepsy (PME) is a group of neurological disorders characterized by recurrent myoclonic seizures with progressive neurological deterioration. We investigated the genetics of three unrelated patients with PME from Mali, a country in sub-Saharan Africa highly underrepresented in genetic and genomic research.

Methods

Participants were carefully examined and phenotyped. DNA was obtained for genetic analysis including whole exome sequencing (WES). In silico prediction tools and ACMG criteria were used to assess the deleteriousness of putative candidate variants.

Results

Pedigree analysis suggests autosomal recessive inheritance patterns for one family and sporadic forms of PME for the two other cases. WES identified novel homozygous missense variants in all the three patients, one each for NHLRC1, EPM2A, and NEU1. The sequence variants segregated with PME in each family and in silico studies including protein 3D structures, CADD scores and ACMG criteria suggested that they were damaging.

Discussion

PME is a group of clinically heterogeneous neurological disorders. Most reported cases in the literature are from European background with only a few cases described in North Africa. We report here novel pathogenic variants in three different genes causing PME phenotypes in three unrelated Malian patients, suggesting that genetic studies of underrepresented populations may expand the genetic epidemiology of PME. These findings also emphasize the need for inclusive genetic research to ensure a more targeted diagnostic and therapeutic approaches for diverse patient populations.

Discovery of a novel mutation F184S (c.551T>C) in GATA4 gene causing congenital heart disease in a consanguineous Saudi family

Background & aim

Congenital heart disease (CHD) is the most common cause of non-infectious deaths in infants worldwide. However, the molecular mechanisms underlying CHD remain unclear. Approximately 30 % of the causes are believed to be genetic mutations and chromosomal abnormalities. In this study, we aimed to identify the genetic causes of CHD in consanguineous families.

Methods

Fourth-generation pedigrees with CHD were recruited. The main cardiac features of the patient included absence of the right pulmonary artery and a large dilated left pulmonary artery. To determine the underlying genetic cause, whole-exome sequencing was performed and subsequently confirmed using Sanger sequencing and different online databases to study the pathogenesis of the identified gene mutation. An in-silico homology model was created using the Alphafold homology model structure of GATA4 (AF-P43694-F1). The missense3D online program was used to evaluate the structural alterations.

Results

We identified a deleterious mutation c.551T > C (p.Phe184Ser) in GATA4. GATA4 is a highly conserved zinc-finger transcription factor, and its continuous expression is essential for cardiogenesis during embryogenesis. The in-silico model suggested a compromised binding efficiency with other proteins. Several variant interpretation algorithms indicated that the F184S missense variant in GATA4 is damaging, whereas HOPE analysis indicated the functional impairment of DNA binding of transcription factors and zinc-ion binding activities of GATA4.

Conclusion

The variant identified in GATA4 appears to cause recessive CHD in the family. In silico analysis suggested that this variant was damaging and caused multiple structural and functional aberrations. This study may support prenatal screening of the fetus in this family to prevent diseases in new generations.

Unraveling the potential effects of non-synonymous single nucleotide polymorphisms (nsSNPs) on the Protein structure and function of the human SLC30A8 gene on type 2 diabetes and colorectal cancer: An In silico approach

Background and aims

The single nucleotide polymorphisms (SNPs) in SLC30A8 gene have been recognized as contributing to type 2 diabetes (T2D) susceptibility and colorectal cancer. This study aims to predict the structural stability, and functional impacts on variations in non-synonymous SNPs (nsSNPs) in the human SLC30A8 gene using various computational techniques.

Materials and methods

Several in silico tools, including SIFT, Predict-SNP, SNPs&GO, MAPP, SNAP2, PhD-SNP, PANTHER, PolyPhen-1,PolyPhen-2, I-Mutant 2.0, and MUpro, have been used in our study.

Results

After data analysis, out of 336 missenses, the eight nsSNPs, namely R138Q, I141N, W136G, I349N, L303R, E140A, W306C, and L308Q, were discovered by ConSurf to be in highly conserved regions, which could affect the stability of their proteins. Project HOPE determines any significant molecular effects on the structure and function of eight mutated proteins and the three-dimensional (3D) structures of these proteins. The two pharmacologically significant compounds, Luzonoid B and Roseoside demonstrate strong binding affinity to the mutant proteins, and they are more efficient in inhibiting them than the typical SLC30A8 protein using Autodock Vina and Chimera. Increased binding affinity to mutant SLC30A8 proteins has been determined not to influence drug resistance. Ultimately, the Kaplan-Meier plotter study revealed that alterations in SLC30A8 gene expression notably affect the survival rates of patients with various cancer types.

Conclusion

Finally, the study found eight highly deleterious missense nsSNPs in the SLC30A8 gene that can be helpful for further proteomic and genomic studies for T2D and colorectal cancer diagnosis. These findings also pave the way for personalized treatments using biomarkers and more effective healthcare strategies.

Marine Compound-Carpatamide D as a Potential Inhibitor Against TOP2A and Its Mutant D1021Y in Colorectal Cancer: Insights from DFT, MEP and Molecular Dynamics Simulation

Colorectal cancer (CRC) ranks as the third most prevalent cancer globally, hence there is an urgent need for new and effective therapeutic options. DNA topoisomerase 2A (TOP2A) plays a crucial role in the cell cycle and is involved in CRC progression, making it essential to identify structural and functional relevant alterations. Among the 24 mutations, our findings indicated that mutation D1021Y has the most deleterious effect on the TOP2A protein. Based on virtual screening of 31,561 compounds, we identified three lead candidates: 17683 (nigrospoxydon C), 28461 (carpatamide D), and 28853 (6'-O-acetyl-isohomaarbutin), which showed promising inhibitory effect against TOP2A and its mutant form. These compounds were assessed for their stability using density functional theory (DFT) analysis, where carpatamide D possessed the least energy gap of 4.398 eV showing its high reactivity among all. Further, molecular docking also shows the carpatamide D as the top candidate, which exhibited favourable docking energy against the TOP2A wild type (- 7.47 kcal/mol) and with D1021Y mutant (- 7.62 kcal/mol) as compared to reference compound PK1, which showed - 6.11 kcal/mol TOP2A wild type and - 6.24 kcal/mol against mutant type. The molecular dynamics simulation was performed to analyse the dynamics and stability of complex, which revealed TOP2A_28641 and D1021Y_28641 complexes to be stable with least root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF). Molecular mechanics/Poisson-Boltzmann surface area calculations indicated that TOP2A_28641 and D1021Y_28641 complexes exhibited the lowest binding energy of - 23.55 kcal/mol and - 25.03 kcal/mol, respectively. Our findings suggest carpatamide D as a promising lead compound for the TOP2A_D1021Y targeted cancer therapies, which needs further experimental validation.

CCDC78: Unveiling the Function of a Novel Gene Associated with Hereditary Myopathy

CCDC78 was identified as a novel candidate gene for autosomal dominant centronuclear myopathy-4 (CNM4) approximately ten years ago. However, to date, only one family has been described, and the function of CCDC78 remains unclear. Here, we analyze for the first time a family harboring a CCDC78 nonsense mutation to better understand the role of CCDC78 in muscle.

METHODS

We conducted a comprehensive histopathological analysis on muscle biopsies, including immunofluorescent assays to detect multiple sarcoplasmic proteins. We examined CCDC78 transcripts and protein using WB in CCDC78-mutated muscle tissue; these analyses were also performed on muscle, lymphocytes, and fibroblasts from healthy subjects. Subsequently, we conducted RT-qPCR and transcriptome profiling through RNA-seq to evaluate changes in gene expression associated with CCDC78 dysfunction in muscle. Lastly, coimmunoprecipitation (Co-Ip) assays and mass spectrometry (LC-MS/MS) studies were carried out on extracted muscle proteins from both healthy and mutated subjects.

RESULTS

The histopathological features in muscle showed novel histological hallmarks, which included areas of dilated and swollen sarcoplasmic reticulum (SR). We provided evidence of nonsense-mediated mRNA decay (NMD), identified the presence of novel CCDC78 transcripts in muscle and lymphocytes, and identified 1035 muscular differentially expressed genes, including several involved in the SR. Through the Co-Ip assays and LC-MS/MS studies, we demonstrated that CCDC78 interacts with two key SR proteins: SERCA1 and CASQ1. We also observed interactions with MYH1, ACTN2, and ACTA1.

CONCLUSIONS

Our findings provide insight, for the first time, into the interactors and possible role of CCDC78 in skeletal muscle, locating the protein in the SR. Furthermore, our data expand on the phenotype previously associated with CCDC78 mutations, indicating potential histopathological hallmarks of the disease in human muscle. Based on our data, we can consider CCDC78 as the causative gene for CNM4.

A comprehensive in silico investigation into the pathogenic SNPs in the RTEL1 gene and their biological consequences

The Regulator of Telomere Helicase 1 (RTEL1) gene encodes a critical DNA helicase intricately involved in the maintenance of telomeric structures and the preservation of genomic stability. Germline mutations in the RTEL1 gene have been clinically associated with Hoyeraal-Hreidarsson syndrome, a more severe version of Dyskeratosis Congenita. Although various research has sought to link RTEL1 mutations to specific disorders, no comprehensive investigation has yet been conducted on missense mutations. In this study, we attempted to investigate the functionally and structurally deleterious coding and non-coding SNPs of the RTEL1 gene using an in silico approach. Initially, out of 1392 nsSNPs, 43 nsSNPs were filtered out through ten web-based bioinformatics tools. With subsequent analysis using nine in silico tools, these 43 nsSNPs were further shortened to 11 most deleterious nsSNPs. Furthermore, analyses of mutated protein structures, evolutionary conservancy, surface accessibility, domains & PTM sites, cancer susceptibility, and interatomic interaction revealed the detrimental effect of these 11 nsSNPs on RTEL1 protein. An in-depth investigation through molecular docking with the DNA binding sequence demonstrated a striking change in the interaction pattern for F15L, M25V, and G706R mutant proteins, suggesting the more severe consequences of these mutations on protein structure and functionality. Among the non-coding variants, two had the highest likelihood of being regulatory variants, whereas one variant was predicted to affect the target region of a miRNA. Thus, this study lays the groundwork for extensive analysis of RTEL1 gene variants in the future, along with the advancement of precision medicine and other treatment modalities.

Structural impact, ligand-protein interactions, and molecular phenotypic effects of TGF-β1 gene variants: In silico analysis with implications for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic Pulmonary Fibrosis (IPF) is a chronic interstitial lung disease resulting in progressively deteriorating lung function. Transforming growth factor-β1 (TGF-β1) belongs to the TGF superfamily and exerts a profibrotic role in promoting lung fibrosis by facilitating fibroblast infiltration and activity, extracellular matrix deposition, and inhibition of collagen breakdown, thus promoting tissue remodelling and IPF.

MATERIALS AND METHODS

We evaluated the link between pathogenic TGF-β1 SNPs and IPF pathogenesis and the structure-activity functional consequences of those SNPs on the TGF-β1 protein. Several computational algorithms were merged to address the functional consequences of TGF-β1 gene mutations to protein stability, putative post-translational modification sites, ligand-protein interactions, and molecular phenotypic effects. These included FATHMM, POLYPHEN2, PROVEAN, and SIFT tools (identifying deleterious nsSNPs in the TGF-β1 gene), along with Pmut, PhD-SNP, SNAP, MutPred and the related TMHMM, MARCOIL, and DisProt algorithms (predicting structural disorders). INPS-MD was also used to evaluate the mutation-induced TGF-β1 protein's stability and MODPRED for recognition of post-translational TGF-β1 modification.

RESULTS

In total, 14 major pathogenic variants markedly impact the destabilization of the TGF-β1 protein, with most of these high-risk mutations associated with decreased stability of the TGF-β1 protein as per the I-Mutant, MUpro, and INPS-MD tools. R205W, R185W, R180Q, D86Y, and I300T variants were proposed to participate in the post-translational modifications, thus affecting affect protein-ligand interactions. Furthermore, at-risk genetic variants appear to target conserved regions in the alpha helices, random coils, and extracellular loops, resulting in a varied composition of amino acids, charge, hydrophobicity, and spatial architecture.

CONCLUSIONS

This study manuscript comprehensively analyzes gene variants within the TGF-β1 gene, offering novel insights into their structural and functional implications in interacting with target sites. This study is significant for the development of targeted therapeutic strategies and personalized treatment approaches for patients with inflammatory lung diseases such as IPF.

Uncovering a Genetic Diagnosis in a Pediatric Patient by Whole Exome Sequencing: A Modeling Investigation in Wiedemann-Steiner Syndrome

Background: Wiedemann-Steiner syndrome (WSS), a rare autosomal-dominant disorder caused by haploinsufficiency of the KMT2A gene product, is part of a group of disorders called chromatinopathies. Chromatinopathies are neurodevelopmental disorders caused by mutations affecting the proteins responsible for chromatin remodeling and transcriptional regulation. The resulting gene expression dysregulation mediates the onset of a series of clinical features such as developmental delay, intellectual disability, facial dysmorphism, and behavioral disorders. Aim of the Study: The aim of this study was to investigate a 10-year-old girl who presented with clinical features suggestive of WSS. Methods: Clinical and genetic investigations were performed. Whole exome sequencing (WES) was used for genetic testing, performed using Illumina technology. The bidirectional capillary Sanger resequencing technique was used in accordance with standard methodology to validate a mutation discovered by WES in all family members who were available. Utilizing computational protein modeling for structural and functional studies as well as in silico pathogenicity prediction models, the effect of the mutation was examined. Results: WES identified a de novo heterozygous missense variant in the KMT2A gene KMT2A(NM_001197104.2): c.3451C>G, p.(Arg1151Gly), absent in the gnomAD database. The variant was classified as Likely Pathogenetic (LP) according to the ACMG criteria and was predicted to affect the CXXC-type zinc finger domain functionality of the protein. Modeling of the resulting protein structure suggested that this variant changes the protein flexibility due to a variation in the Gibbs free energy and in the vibrational entropy energy difference between the wild-type and mutated domain, resulting in an alteration of the DNA binding affinity. Conclusions: A novel and de novo mutation discovered by the NGS approach, enhancing the mutation spectrum in the KMT2A gene, was characterized and associated with WSS. This novel KMT2A gene variant is suggested to modify the CXXC-type zinc finger domain functionality by affecting protein flexibility and DNA binding.

A Novel Autosomal Recessive Candidate Gene Responsible for RASopathy-Like Phenotype and Bone Marrow Failure: RASA3

Although many genetic etiologies, such as Fanconi anemia, Shwachman-Diamond syndrome, dyskeratosis congenita, and Diamond-Blackfan anemia, from hereditary bone marrow failure are known today, the responsible gene remains unknown in a significant part of these patients. A 6-year-old girl, whose parents were first-cousin consanguineous, was referred to the pediatric hematology department due to growth retardation, thrombocytopenia, neutropenia, and anemia. The patient had low-set ears, pectus excavatum inferiorly, and cafe-au-lait spots. In whole-exome analysis, p.K385T (c.1154A > C) variant in the RASA3 gene was detected as homozygous. The amino acid position of the alteration is located in the conserved and ordered region, corresponding to the Ras GTPase activation domain (Ras-GAP) in the center of the protein. Importantly, most of in silico prediction tools of pathogenicity predicts the variant as damaging. RASopathies, which are characterized by many common clinical findings, such as atypical facial features, growth delays, and heart defects, are a group of rare genetic diseases caused by mutations in the genes involved in the Ras-MAPK pathway. The findings in this patient were consistent with the RASopathy-like phenotype and bone marrow failure. Interestingly, enrichment of RASopathy genes was observed in the RASA3 protein-protein interaction network. Furthermore, the subsequent topological clustering revealed a putative function module, which further implicates RASA3 in this disease as a novel potential causative gene. In this context, the detected RASA3 mutation could be manifesting itself clinically as the observed phenotype by disrupting the functional cooperation between the RASA3 protein and its interaction partners. Relatedly, current literature also supports the obtained findings. Overall, this study provides new insights into RASopathy and put forward the RASA3 gene as a novel candidate gene for this disease group.

A Village in the Southeastern Region of Iran Harboring the c.716T>A (p.Val239Asp) Mutation in SLC26A4

After GJB2, SLC26A4 is the second most common contributor to autosomal recessive nonsyndromic hearing loss (ARNSHL) worldwide. In this study, we used Exome Sequencing (ES) to present a village with 31 individuals affected by hereditary hearing loss (HHL) in southeastern Iran near the border of Pakistan. The village harbored the known pathogenic missense SLC26A4 (NM_000441.2):c.716T>A (p.Val239Asp) mutation, which has a founder effect attributed to Pakistan, Iran's southeastern neighbor. Our findings, in addition to unraveling the molecular cause of non-syndromic hearing loss in these patients and further confirming the common ancestry and migration story between the people of this region and Pakistan, provide further insight into the genetic background of this region and highlight the importance of understanding the mutation spectrum of GJB2 and SLC26A4 in different regions to choose cost-effective strategies for molecular genetic testing.

Identification of rare missense variants in the BSN gene co-segregating with chronic otitis media in a consanguineous Pakistani family

BACKGROUND

Otitis media (OM) is the most frequent and complex middle ear condition with multifactorial etiology including genetic predisposition. OM depicts a variable clinical spectrum, leading to speech, developmental delay, and hearing loss. Here, we report the clinical and genetic findings of chronic suppurative otitis media (CSOM) segregating in a six-generation consanguineous Pakistani family PKOM08.

METHODS

Clinical evaluations, including audio and tympanometry, were conducted to assess OM manifestation and their impact on hearing function. Exome sequencing was performed to identify potential genetic variants underlying CSOM in the study participants.

RESULTS

Clinical evaluation of participating individuals revealed varying degrees of disease severity, with mild to moderate hearing loss. All the affected individuals had CSOM with no other apparent comorbidity. Whole exome followed by Sanger sequencing revealed two rare heterozygous variants [c.1867C>T, p.(Pro623Ser) and c.11015G>A, p.(Arg3672Gln)] of BSN gene in most of the affected individuals of family PKOM08. BSN encodes a scaffold bassoon protein involved in synaptic vesicle trafficking. The identified variants replaced evolutionary conserved amino acid residues in the encoded protein and are predicted to impact the ionic interactions in the secondary structure.

CONCLUSION

A deep intronic variant of BSN has been previously implicated in the etiology of childhood ear infections. Our study further supports a link between BSN-impaired function and ear infection and CSOM in children.

Evidence for NR2F2/COUP-TFII involvement in human testis development

NR2F2 encodes COUP-TFII, an orphan nuclear receptor required for the development of the steroidogenic lineages of the murine fetal testes and ovaries. Pathogenic variants in human NR2F2 are associated with testis formation in 46,XX individuals, however, the function of COUP-TFII in the human testis is unknown. We report a de novo heterozygous variant in NR2F2 (c.737G > A, p.Arg246His) in a 46,XY under-masculinized boy with primary hypogonadism. The variant, located within the ligand-binding domain, is predicted to be highly damaging. In vitro studies indicated that the mutation does not impact the stability or subcellular localization of the protein. NR5A1, a related nuclear receptor that is a key factor in gonad formation and function, is known to physically interact with COUP-TFII to regulate gene expression. The mutant protein did not affect the physical interaction with NR5A1. However, in-vitro assays demonstrated that the mutant protein significantly loses the inhibitory effect on NR5A1-mediated activation of both the LHB and INSL3 promoters. The data support a role for COUP-TFII in human testis formation. Although mutually antagonistic sets of genes are known to regulate testis and ovarian pathways, we extend the list of genes, that together with NR5A1 and WT1, are associated with both 46,XX and 46,XY DSD.

Novel TMPRSS6 variants and their impact on iron-refractory iron deficiency anaemia in pregnancy: A North Indian genotype phenotype study

Iron-refractory iron deficiency anaemia (IRIDA) is a rare autosomal recessive disorder, distinguished by hypochromic microcytic anaemia, low transferrin levels and inappropriately elevated hepcidin (HEPC) levels. It is caused by mutations in TMPRSS6 gene. Systematic screening of 500 pregnant women with iron deficiency anaemia having moderate to severe microcytosis with no other causes of anaemia were enrolled to rule out oral iron refractoriness. It identified a final cohort of 10 (2.15% prevalence) individuals with IRIDA phenotype. Haematological and biochemical analysis revealed significant differences between iron responders and iron non-responders, with iron non-responders showing lower haemoglobin, red blood cell count, serum iron and serum ferritin levels, along with elevated HEPC (9.47 ± 2.75 ng/mL, p = 0.0009) and erythropoietin (4.58 ± 4.07 µ/mL, p = 0.0196) levels. Genetic sequencing of the TMPRSS6 gene in this final cohort identified 10 novel variants, including seven missense and three frame-shift mutations, with four missense variants showing high functional impact defining the IRIDA phenotype. Structural analysis revealed significant damage caused by two variants (p.L83R and p.S235R). This study provides valuable insights into IRIDA among pregnant women in the Indian subcontinent, unveiling its underlying causes of unresponsiveness, genetic mechanisms and prevalence. Furthermore, research collaboration is essential to validate these findings and develop effective treatments.

In Silico Functional and Structural Analysis of Non-synonymous Single Nucleotide Polymorphisms (nsSNPs) in Human Paired Box 4 Gene

In human genome, members of Paired box (PAX) transcription factor family are highly sequence-specific DNA-binding proteins. Among PAX gene family members, PAX4 gene has significant role in growth, proliferation, differentiation, and insulin secretion of pancreatic β-cells. Single nucleotide polymorphisms (SNPs) in PAX4 gene progress in the pathogenesis of various human diseases. Hence, the molecular mechanism of how these SNPs in PAX4 gene significantly progress diseases pathogenesis needs to be elucidated. For the reason, a series of bioinformatic analyzes were done to identify the SNPs of PAX4 gene that contribute in diseases pathogenesis. From the analyzes, 4145 SNPs (rsIDs) in PAX4 gene were obtained, where, 362 missense (8.73%), 169 synonymous (4.08%), and 2323 intron variants (56.04%). The rest SNPs were unspecified. Among the 362 missense variants, 118 nsSNPs were found as deleterious in SIFT analysis. Among those, 25 nsSNPs were most probably damaging and 23 were deleterious as observed in PolyPhen-2 and PROVEAN analyzes, respectively. Following all analyzes, 14 nsSNPs (rs149708455, rs115887120, rs147279315, rs35155575, rs370095957, rs373939873, rs145468905, rs121917718, rs2233580, rs3824004, rs372751660, rs369459316, rs375472849, rs372497946) were common and observed as deleterious, probably damaging, affective and diseases associated. Following structural analyzes, 11 nsSNPs guided proteins were found as most unstable and highly conserved. Among these, R20W, R39Q, R45Q, R60H, G65D, and A223D mutated proteins were highly harmful. Hence, the results from above-mentioned integrated comprehensive bioinformatic analyzes guide how different nsSNPs in PAX4 gene alter structural and functional characteristics of the protein that might progress diseases pathogenesis in human including type 2 diabetes.

Molecular insights into TP53 mutation (p. Arg267Trp) and its connection to Choroid Plexus Carcinomas and Li-Fraumeni Syndrome

BACKGROUND

Choroid plexus carcinomas (CPCs) are rare malignant tumors primarily affecting pediatric patients and often co-occur with Li-Fraumeni Syndrome (LFS), an inherited predisposition to early-onset malignancies in multiple organ systems. LFS is closely linked to TP53 mutations, with germline TP53 gene mutations present in approximately 75% of Li-Fraumeni syndrome families and 25% of Li-Fraumeni-like syndrome families. Individuals with TP53 mutations also have an elevated probability of carrying mutations in BRCA1 and BRCA2 genes.

OBJECTIVE

To investigate the structural and functional implications of the TP53: 799C > T, p. (Arg267Trp) missense mutation, initially identified in a Saudi family, and understand its impact on TP53 functionality and related intermolecular interactions.

METHODS

Computational analyses were conducted to examine the structural modifications resulting from the TP53: 799C > T, p. (Arg267Trp) mutation. These analyses focused on the mutation's impact on hydrogen bonding, ionic interactions, and the specific interaction with Cell Cycle and Apoptosis Regulator 2 (CCAR2), as annotated in UniProt.

RESULTS

The study revealed that the native Arg267 residue is critical for a salt bridge interaction with glutamic acid at position 258. The mutation-induced charge alteration has the potential to disrupt this ionic bonding. Additionally, the mutation is located within an amino acid region crucial for interaction with CCAR2. The altered properties of the amino acid within this domain may affect its functionality and disrupt this interaction, thereby impacting the regulation of catalytic enzyme activity.

CONCLUSIONS

Our findings highlight the intricate intermolecular interactions governing TP53 functionality. The TP53: 799C > T, p. (Arg267Trp) mutation causes structural modifications that potentially disrupt critical ionic bonds and protein interactions, offering valuable insights for the development of targeted mutants with distinct functional attributes. These insights could inform therapeutic strategies for conditions associated with TP53 mutations.

A computational workflow for analysis of missense mutations in precision oncology

Every year, more than 19 million cancer cases are diagnosed, and this number continues to increase annually. Since standard treatment options have varying success rates for different types of cancer, understanding the biology of an individual's tumour becomes crucial, especially for cases that are difficult to treat. Personalised high-throughput profiling, using next-generation sequencing, allows for a comprehensive examination of biopsy specimens. Furthermore, the widespread use of this technology has generated a wealth of information on cancer-specific gene alterations. However, there exists a significant gap between identified alterations and their proven impact on protein function. Here, we present a bioinformatics pipeline that enables fast analysis of a missense mutation's effect on stability and function in known oncogenic proteins. This pipeline is coupled with a predictor that summarises the outputs of different tools used throughout the pipeline, providing a single probability score, achieving a balanced accuracy above 86%. The pipeline incorporates a virtual screening method to suggest potential FDA/EMA-approved drugs to be considered for treatment. We showcase three case studies to demonstrate the timely utility of this pipeline. To facilitate access and analysis of cancer-related mutations, we have packaged the pipeline as a web server, which is freely available at https://loschmidt.chemi.muni.cz/predictonco/ .Scientific contributionThis work presents a novel bioinformatics pipeline that integrates multiple computational tools to predict the effects of missense mutations on proteins of oncological interest. The pipeline uniquely combines fast protein modelling, stability prediction, and evolutionary analysis with virtual drug screening, while offering actionable insights for precision oncology. This comprehensive approach surpasses existing tools by automating the interpretation of mutations and suggesting potential treatments, thereby striving to bridge the gap between sequencing data and clinical application.

Silibinins and curcumin as promising ligands against mutant cystic fibrosis transmembrane regulator protein

Cystic Fibrosis Transmembrane Regulator (CFTR) is a significant protein that is responsible for the movement of ions across cell membranes. The cystic fibrosis (CF) occur due to the mutations in the CFTR gene as it produces the dysfunctional CFTR protein. The sequence of CFTR protein as a target structure was retrieved from UniProt and PDB database. The ligands selection was performed through virtual screening and top 3 ligands choose out of 65 ligands silibinins, curcumin, demethoxycurcumin were selected with a reference drug Trikafta (R*). According to docking, ADMET analyses, the natural ligands (Silibinins and Curcumin) displayed best binding energy, pharmacokinetic and free toxicity than other natural compounds and reference drug (R*). An MD simulation for 200 ns was also established to ensure that natural ligands (Silibinins and Curcumin) attached to the target protein favorably and dynamically, and that protein-ligand complex stability was maintained. It is concluded that silibinins and curcumins have a better capacity to decrease the effect of mutant CFTR protein through improved trafficking and the restoration of original function. In conclusion, in silico studies demonstrate the potential of silibinins and curcumin as therapeutic agents for cystic fibrosis, particularly for the D614G mutated protein. Their ability to increase CFTR function while reducing cellular stress and inflammation, together with their favorable safety profile and accessibility could make them valuable additions to cystic fibrosis treatment options. Further experimental and clinical validation will be required to fully realize their potential and include them into effective therapy regimens.

Machine Learning of Three-Dimensional Protein Structures to Predict the Functional Impacts of Genome Variation

Research in the human genome sciences generates a substantial amount of genetic data for hundreds of thousands of individuals, which concomitantly increases the number of variants of unknown significance (VUS). Bioinformatic analyses can successfully reveal rare variants and variants with clear associations with disease-related phenotypes. These studies have had a significant impact on how clinical genetic screens are interpreted and how patients are stratified for treatment. There are few, if any, computational methods for variants comparable to biological activity predictions. To address this gap, we developed a machine learning method that uses protein three-dimensional structures from AlphaFold to predict how a variant will influence changes to a gene's downstream biological pathways. We trained state-of-the-art machine learning classifiers to predict which protein regions will most likely impact transcriptional activities of two proto-oncogenes, nuclear factor erythroid 2 (NFE2L2)-related factor 2 (NRF2) and c-Myc. We have identified classifiers that attain accuracies higher than 80%, which have allowed us to identify a set of key protein regions that lead to significant perturbations in c-Myc or NRF2 transcriptional pathway activities.

Variants of NAV3, a neuronal morphogenesis protein, cause intellectual disability, developmental delay, and microcephaly

Microtubule associated proteins (MAPs) are widely expressed in the central nervous system, and have established roles in cell proliferation, myelination, neurite formation, axon specification, outgrowth, dendrite, and synapse formation. We report eleven individuals from seven families harboring predicted pathogenic biallelic, de novo, and heterozygous variants in the NAV3 gene, which encodes the microtubule positive tip protein neuron navigator 3 (NAV3). All affected individuals have intellectual disability (ID), microcephaly, skeletal deformities, ocular anomalies, and behavioral issues. In mouse brain, Nav3 is expressed throughout the nervous system, with more prominent signatures in postmitotic, excitatory, inhibiting, and sensory neurons. When overexpressed in HEK293T and COS7 cells, pathogenic variants impaired NAV3 ability to stabilize microtubules. Further, knocking-down nav3 in zebrafish led to severe morphological defects, microcephaly, impaired neuronal growth, and behavioral impairment, which were rescued with co-injection of WT NAV3 mRNA and not by transcripts encoding the pathogenic variants. Our findings establish the role of NAV3 in neurodevelopmental disorders, and reveal its involvement in neuronal morphogenesis, and neuromuscular responses.

Germline Sequencing of DNA Damage Repair Genes in Two Hereditary Prostate Cancer Cohorts Reveals New Disease Risk-Associated Gene Variants

Rare, inherited variants in DNA damage repair (DDR) genes have a recognised role in prostate cancer (PrCa) susceptibility. In addition, these genes are therapeutically targetable. While rare variants are informing clinical management in other common cancers, defining the rare disease-associated variants in PrCa has been challenging. Here, whole-genome and -exome sequencing data from two independent, high-risk Australian and North American familial PrCa datasets were interrogated for novel DDR risk variants. Rare DDR gene variants (predicted to be damaging and present in two or more family members) were identified and subsequently genotyped in 1963 individuals (700 familial and 459 sporadic PrCa cases, 482 unaffected relatives, and 322 screened controls), and association analyses accounting for relatedness (MQLS) undertaken. In the combined datasets, rare ERCC3 (rs145201970, p = 2.57 × 10-4) and BRIP1 (rs4988345, p = 0.025) variants were significantly associated with PrCa risk. A PARP2 (rs200603922, p = 0.028) variant in the Australian dataset and a MUTYH (rs36053993, p = 0.031) variant in the North American dataset were also associated with risk. Evaluation of clinicopathological characteristics provided no evidence for a younger age or higher-grade disease at diagnosis in variant carriers, which should be taken into consideration when determining genetic screening eligibility criteria for targeted, gene-based treatments in the future. This study adds valuable knowledge to our understanding of PrCa-associated DDR genes, which will underpin effective clinical screening and treatment strategies.

Computational screening of pathogenic missense nsSNPs in heme oxygenase 1 (HMOX1) gene and their structural and functional consequences

Heme Oxygenase 1 (HMOX1) is a cytoprotective enzyme, exhibiting the highest activity in the spleen, catalyzing the heme ring breakdown into products of biological significance- biliverdin, CO, and Fe2+. In vascular cells, HMOX1 possesses strong anti-apoptotic, antioxidant, anti-proliferative, anti-inflammatory, and immunomodulatory actions. The majority of these activities are crucial for the prevention of atherogenesis. Single amino acid substitutions in proteins generated by missense non-synonymous single nucleotide polymorphism (nsSNPs) in the protein-encoding regions of genes are potent enough to cause significant medical challenges due to the alteration of protein structure and function. The current study aimed at characterizing and analyzing high-risk nsSNPs associated with the human HMOX1 gene. Preliminary screening of the total available 288 missense SNPs was performed through the lens of deleteriousness and stability prediction tools. Finally, a total of seven nsSNPs (Y58D, A131T, Y134H, F166S, F167S, R183S and M186V) were found to be most deleterious by all tools that are present at highly conserved positions. Molecular dynamics simulations (MDS) analysis explained the mutational effects on the dynamic action of the wild-type and mutant proteins. In a nutshell, R183S (rs749644285) was identified as a highly detrimental mutation that could significantly render the enzymatic activity of HMOX1. The finding of this computational analysis might help subject the experimental confirmatory analysis to characterize the role of nsSNPs in HMOX1.Communicated by Ramaswamy H. Sarma.

Structural and functional insights into a novel homozygous missense pathogenic variant in CUL7 identified in consanguineous Pakistani family

3M syndrome is a rare genetic familial disorder characterized by short stature, growth retardation, facial dysmorphism, skeletal abnormalities, fleshy protruding heels, and normal intelligence, caused by mutations in the CUL7, OBSL1 and CCDC8 genes. In the present study, a novel homozygous missense variant of CUL7 (NP_001161842.1, c.4493T > C, p.L1498P) has been identified in a consanguineous Pakistani family by whole exome sequencing. In silico structural evaluation, molecular docking and simulation studies of mutant CUL7 provides substantial evidence about its crucial role in the progression of discussed ailment. The newly discovered variant significantly altered the protein's three dimensional structure, leading to abnormal interaction with binding proteins. This computational and experimental investigation provides useful information to drug developers for the synthesis of novel therapeutics against the discussed ailment.Communicated by Ramaswamy H. Sarma.

Computational exploration of SLC14A1 genetic variants through structure modeling, protein-ligand docking, and molecular dynamics simulation

The urea transporter UT-B1, encoded by the SLC14A1 gene, has been hypothesized to be a significant protein whose deficiency and dysfunction contribute to the pathogenesis of bladder cancer and many other diseases. Several studies reported the association of genetic alterations in the SLC14A1 (UT-B1) gene with bladder carcinogenesis, suggesting a need for thorough characterization of the UT-B1 protein's coding and non-coding variants. This study used various computational techniques to investigate the commonly occurring germ-line missense and non-coding SNPs (ncSNPs) of the SLC14A1 gene (UT-B1) for their structural, functional, and molecular implications for disease susceptibility and dysfunctionality. SLC14A1 missense variants, primarily identified from the ENSEMBL genome browser, were screened through twelve functionality prediction tools leading to two variants D280Y (predicted detrimental by maximum tools) and D280N (high global MAF) for rs1058396. Subsequently, the ConSurf and NetSurf tools revealed the D280 residue to be in a variable site and exposed on the protein surface. According to I-Mutant2.0 and MUpro, both variants are predicted to cause a significant effect on protein stability. Analysis of molecular docking anticipated these two variants to decrease the binding affinity of UT-B1 protein for the examined ligands to a significant extent. Molecular dynamics also disclosed the possible destabilization of the UT-B1 protein due to single nucleotide polymorphism compared to wild-type protein which may result in impaired protein function. Furthermore, several non-coding SNPs were estimated to affect transcription factor binding and regulation of SLC14A1 gene expression. Additionally, two ncSNPs were found to affect miRNA-based post-transcriptional regulation by creating new seed regions for miRNA binding. This comprehensive in-silico study of SLC14A1 gene variants may serve as a springboard for future large-scale investigations examining SLC14A1 polymorphisms.

Investigating the structural and functional consequences of germline single nucleotide polymorphisms located in the genes of the alternative lengthening of telomere (ALT) pathway

Background

The Alternative Lengthening of Telomeres (ALT) pathway represents a non-canonical mechanism of telomere maintenance that operates independently of the conventional telomerase activity. The three biologically significant proteins, designated as SMARCAL1 (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A-like protein 1), DAXX (Death domain-associated protein 6) and ATRX (alpha-thalassemia/mental retardation, X-linked) are associated with ALT in certain cancer types. The purpose of this study was to identify the most high-risk nsSNPs (non-synonymous Single Nucleotide Polymorphisms) within these three genes and assess their impacts on the structure and function of the proteins they encode.

Methods

The reported genetic polymorphisms of SMARCAL1, DAXX and ATRX genes were retrieved from the Ensembl database. Later, various computational tools like PROVEAN, PolyPhen2, SNPs and GO, SNAP2, Predict-SNP, Panther and PMut were used to predict the most deleterious nsSNPs. MutPred was used to understand the underlying molecular reasons of those nsSNPs being deleterious, followed by prediction of Post Translational Modification Sites (PTMs) using ModPred. I-Mutant and MUpro were used to predict the effect of SNP on energy stability. Later, 3D clustering analysis was done using Mutation 3D server. Moreover, ConSurf was utilized to identify the conservation scores of wild-type amino acids. Additionally, the NCBI conserved domain search tool was employed to pinpoint conserved domains within these three proteins. Project-Hope helped for biophysical validation, followed by prediction of these genes' interaction and function by using GeneMANIA.

Result

Analysis on SMARCAL1 protein revealed that among 665 nsSNPs, four were identified as the most deleterious: L578S, T581S, P582A, and P582S. Similarly, within the DAXX protein, among a pool of 480 nsSNPs, P284S, R230C, and R230S were found out to be the most deleterious variants. In case of ATRX protein, V178D, R246C, and V277G, from the total of 1009 nsSNPs, were predicted to be the most deleterious. All these nsSNPs were found to occur at residue positions that are 100 % conserved within protein domains and were predicted to be most damaging from both structural and functional perspectives and highly destabilizing to their corresponding proteins.

Conclusion

Computational investigation on the 3 proteins-SMARCAL1, DAXX and ATRX through different bioinformatics analysis tools concludes that the identified high risk nsSNPs of these proteins are pathogenic SNPs. These variants potentially exert functional and structural influences, thus making them valuable candidates for future genetic studies.

Prediction and assessment of deleterious and disease causing nonsynonymous single nucleotide polymorphisms (nsSNPs) in human FOXP4 gene: An in - silico study

In humans, FOXP gene family is involved in embryonic development and cancer progression. The FOXP4 (Forkhead box protein P4) gene belongs to this FOXP gene family. FOXP4 gene plays a crucial role in oncogenesis. Single nucleotide polymorphisms are biological markers and common determinants of human diseases. Mutations can largely affect the function of the corresponding protein. Therefore, the molecular mechanism of nsSNPs in the FOXP4 gene needs to be elucidated. Initially, the SNPs of the FOXP4 gene were extracted from the dbSNP database and a total of 23124 SNPs was found, where 555 nonsynonymous, 20525 intronic, 1114 noncoding transcript, 334 synonymous were obtained and the rest were unspecified. Then, a series of bioinformatics tools (SIFT, PolyPhen2, SNAP2, PhD SNP, PANTHER, I-Mutant2.0, MUpro, GOR IV, ConSurf, NetSurfP 2.0, HOPE, DynaMut2, GeneMANIA, STRING and Schrodinger) were used to explore the effect of nsSNPs on FOXP4 protein function and structural stability. First, 555 nsSNPs were analyzed using SIFT, of which 57 were found as deleterious. Following, PolyPhen2, SNAP2, PhD SNP and PANTHER analyses, 10 nsSNPs (rs372762294, rs141899153, rs142575732, rs376938850, rs367607523, rs112517943, rs140387832, rs373949416, rs373949416 and rs376160648) were common and observed as deleterious, damaging and diseases associated. Following that, using I-Mutant2.0 and MUpro servers, 7 nsSNPs were found to be the most unstable. GOR IV predicted that these seven nsSNPs affect protein structure by altering the protein contents of alpha helixes, extended strands, and random coils. Following DynaMut2, 5 nsSNPs showed a decrease in the ΔΔG value compared with the wild-type and were found to be responsible for destabilizing the corresponding protein. GeneMANIA and STRING network revealed interaction of FOXP4 with other genes. Finally, molecular dynamics simulation analysis revealed consistent fluctuation in RMSD and RMSF values, Rg and hydrogen bonds in the mutant proteins compared with WT, which might alter the functional and structural stability of the corresponding protein. As a result, the aforementioned integrated comprehensive bioinformatic analyses provide insight into how various nsSNPs of the FOXP4 gene change the structural and functional properties of the corresponding protein, potentially proceeding with the pathophysiology of human diseases.

A comprehensive examination of ACE2 receptor and prediction of spike glycoprotein and ACE2 interaction based on in silico analysis of ACE2 receptor

The ACE2 receptor plays a vital role not only in the SARS-CoV-induced epidemic but also in various other diseases, including cardiovascular diseases and ARDS. While studies have explored the interactions between ACE2 and SARS-CoV proteins, comprehensive research utilizing bioinformatic tools on the ACE2 protein has been lacking. The one aim of present study was to extensively analyze the regions of the ACE2 protein. After utilizing all bioinformatics tools especially G104 and L108 regions on ACE2 were come forward. The results of our analysis revealed that possible mutations or deletions in the G104 and L108 regions play a critical role in both the biological functioning and the determination of the chemical-physical properties of ACE2. Additionally, these regions were found to be more susceptible to mutations or deletions compared to other regions of the ACE2 protein. Notably, the randomly selected peptide, LQQNGSSVLS (100-109), which includes G104 and L108, exhibited a crucial role in binding the RBD of the spike protein, as supported by docking scores. Furthermore, both MDs and iMODs results provided evidence that G104 and L108 influence the dynamics of ACE2-spike complexes. This study is expected to offer a new perspective on the ACE2-SARS-CoV interaction and other research areas where ACE2 plays a significant role, such as biotechnology (protein engineering, enzyme optimization), medicine (RAS, pulmonary and cardiac diseases), and basic research (structural motifs, stabilizing protein folds, or facilitating important inter molecular contacts, protein's proper structure and function).Communicated by Ramaswamy H. Sarma.

Mechanistic insights into the conformational changes and alterations in residual communications due to the mutations in the pncA Gene of Mycobacterium tuberculosis: A computational perspective for effective therapeutic solutions

Due to its emerging resistance to first-line anti-TB medications, tuberculosis (TB) is one of the most contagious illness in the world. According to reports, the effectiveness of treating TB is severely impacted by drug resistance, notably resistance caused by mutations in the pncA gene-encoded pyrazinamidase (PZase) to the front-line drug pyrazinamide (PZA). The present study focused on investigating the resistance mechanism caused by the mutations D12N, T47A, and H137R to better understand the structural and molecular events responsible for the resistance acquired by the pncA gene of Mycobacterium tuberculosis (MTB) at the structural level. Bioinformatics analysis predicted that all three mutations were deleterious and located near the active centre of the pncA, affecting its functional activity. Furthermore, molecular dynamics simulation (MDS) results established that mutations significantly reduced the structural stability and caused the rearrangement of FE2+ in the active centre of pncA. Moreover, essential dynamics analysis, including principal component analysis (PCA) and free energy landscape (FEL), concluded variations in the protein motion and decreased conformational space in the mutants. Additionally, the mutations potentially impacted the network topologies and altered the residual communications in the network. The complex simulation study results established the significant movement of the flap region from the active centre of mutant complexes, further supporting the flap region's significance in developing resistance to the PZA drug. This study advances our knowledge of the primary cause of the mechanism of PZA resistance and the structural dynamics of pncA mutants, which will help us to design new and potent chemical scaffolds to treat drug-resistant TB (DR-TB).

Diverse genetic causes of amenorrhea in an ethnically homogeneous cohort and an evolving approach to diagnosis

RESEARCH QUESTION

Premature ovarian insufficiency (POI) is characterised by amenorrhea associated with elevated follicle stimulating hormone (FSH) under the age of 40 years and affects 1-3.7% women. Genetic factors explain 20-30% of POI cases, but most causes remain unknown despite genomic advancements.

DESIGN

We used whole exome sequencing (WES) in four Iranian families, validated variants via Sanger sequencing, and conducted the Acyl-cLIP assay to measure HHAT enzyme activity.

RESULTS

Despite ethnic homogeneity, WES revealed diverse genetic causes, including a novel homozygous nonsense variant in SYCP2L, impacting synaptonemal complex (SC) assembly, in the first family. Interestingly, the second family had two independent causes for amenorrhea - the mother had POI due to a novel homozygous loss-of-function variant in FANCM (required for chromosomal stability) and her daughter had primary amenorrhea due to a novel homozygous GNRHR (required for gonadotropic signalling) frameshift variant. WES analysis also provided cytogenetic insights. WES revealed one individual was in fact 46, XY and had a novel homozygous missense variant of uncertain significance in HHAT, potentially responsible for complete sex reversal although functional assays did not support impaired HHAT activity. In the remaining individual, WES indicated likely mosaic Turners with the majority of X chromosome variants having an allelic balance of ∼85% or ∼15%. Microarray validated the individual had 90% 45,XO.

CONCLUSIONS

This study demonstrates the diverse causes of amenorrhea in a small, isolated ethnic cohort highlighting how a genetic cause in one individual may not clarify familial cases. We propose that, in time, genomic sequencing may become a single universal test required for the diagnosis of infertility conditions such as POI.

Expanding the phenotypic spectrum of LHCGR signal peptide insertion variant: novel clinical and allelic findings causing Leydig cell hypoplasia type II

PURPOSE

Leydig cell hypoplasia (LCH) type II is a rare disease with only a few cases reported. Patients presented with hypospadias, micropenis, undescended testes, or infertility. In this study, we report a new patient with compound heterozygous variants in the LHCGR gene and LCH type II phenotype.

METHODS

Whole exome sequencing (WES) was performed followed by Sanger sequencing to confirm the detected variants in the patient and his parents.

RESULTS

A novel missense variant (p.Phe444Cys) was identified in a highly conserved site and is verified to be in trans with the signal peptide's 33-bases insertion variant.

CONCLUSION

Our research provides a more comprehensive clinical and genetic spectrum of Leydig cell hypoplasia type II. It highlighted the importance of WES in the diagnosis of this uncommon genetic disorder as well as the expansion of the genotype of LCH type II.

A computational approach for structural and functional analyses of disease-associated mutations in the human CYLD gene

Tumor suppressor cylindromatosis protein (CYLD) regulates NF-κB and JNK signaling pathways by cleaving K63-linked poly-ubiquitin chain from its substrate molecules and thus preventing the progression of tumorigenesis and metastasis of the cancer cells. Mutations in CYLD can cause aberrant structure and abnormal functionality leading to tumor formation. In this study, we utilized several computational tools such as PANTHER, PROVEAN, PredictSNP, PolyPhen-2, PhD-SNP, PON-P2, and SIFT to find out deleterious nsSNPs. We also highlighted the damaging impact of those deleterious nsSNPs on the structure and function of the CYLD utilizing ConSurf, I-Mutant, SDM, Phyre2, HOPE, Swiss-PdbViewer, and Mutation 3D. We shortlisted 18 high-risk nsSNPs from a total of 446 nsSNPs recorded in the NCBI database. Based on the conservation profile, stability status, and structural impact analysis, we finalized 13 nsSNPs. Molecular docking analysis and molecular dynamic simulation concluded the study with the findings of two significant nsSNPs (R830K, H827R) which have a remarkable impact on binding affinity, RMSD, RMSF, radius of gyration, and hydrogen bond formation during CYLD-ubiquitin interaction. The principal component analysis compared native and two mutants R830K and H827R of CYLD that signify structural and energy profile fluctuations during molecular dynamic (MD) simulation. Finally, the protein-protein interaction network showed CYLD interacts with 20 proteins involved in several biological pathways that mutations can impair. Considering all these in silico analyses, our study recommended conducting large-scale association studies of nsSNPs of CYLD with cancer as well as designing precise medications against diseases associated with these polymorphisms.

In Silico Characterization of Pathogenic Homeodomain Missense Mutations in the PITX2 Gene

Paired homologous domain transcription factor 2 (PITX2) is critically involved in ocular and cardiac development. Mutations in PITX2 are consistently reported in association with Axenfeld-Rieger syndrome, an autosomal dominant genetic disorder and atrial fibrillation, a common cardiac arrhythmia. In this study, we have mined missense mutations in PITX2 gene from NCBI-dbSNP and Ensembl databases, evaluated the pathogenicity of the missense variants in the homeodomain and C-terminal region using five in silico prediction tools SIFT, PolyPhen2, GERP, Mutation Assessor and CADD. Fifteen homeodomain mutations G42V, G42R, R45W, S49Y, R53W, E53D, E55V, R62H, P65S, R69H, G75R, R84G, R86K, R87W, R91P were found to be highly pathogenic by both SIFT, PolyPhen2 were further functionally characterized using I-Mutant 2.0, Consurf, MutPred and Project Hope. The findings of the study can be used for prioritizing mutations in the context of genetic studies.

In silico functional, structural and pathogenicity analysis of missense single nucleotide polymorphisms in human MCM6 gene

Single nucleotide polymorphisms (SNPs) are one of the most common determinants and potential biomarkers of human disease pathogenesis. SNPs could alter amino acid residues, leading to the loss of structural and functional integrity of the encoded protein. In humans, members of the minichromosome maintenance (MCM) family play a vital role in cell proliferation and have a significant impact on tumorigenesis. Among the MCM members, the molecular mechanism of how missense SNPs of minichromosome maintenance complex component 6 (MCM6) contribute to DNA replication and tumor pathogenesis is underexplored and needs to be elucidated. Hence, a series of sequence and structure-based computational tools were utilized to determine how mutations affect the corresponding MCM6 protein. From the dbSNP database, among 15,009 SNPs in the MCM6 gene, 642 missense SNPs (4.28%), 291 synonymous SNPs (1.94%), and 12,500 intron SNPs (83.28%) were observed. Out of the 642 missense SNPs, 33 were found to be deleterious during the SIFT analysis. Among these, 11 missense SNPs (I123S, R207C, R222C, L449F, V456M, D463G, H556Y, R602H, R633W, R658C, and P815T) were found as deleterious, probably damaging, affective and disease-associated. Then, I123S, R207C, R222C, V456M, D463G, R602H, R633W, and R658C missense SNPs were found to be highly harmful. Six missense SNPs (I123S, R207C, V456M, D463G, R602H, and R633W) had the potential to destabilize the corresponding protein as predicted by DynaMut2. Interestingly, five high-risk mutations (I123S, V456M, D463G, R602H, and R633W) were distributed in two domains (PF00493 and PF14551). During molecular dynamics simulations analysis, consistent fluctuation in RMSD and RMSF values, high Rg and hydrogen bonds in mutant proteins compared to wild-type revealed that these mutations might alter the protein structure and stability of the corresponding protein. Hence, the results from the analyses guide the exploration of the mechanism by which these missense SNPs of the MCM6 gene alter the structural integrity and functional properties of the protein, which could guide the identification of ways to minimize the harmful effects of these mutations in humans.

Qualitative Immunoglobulin Deficiency Causes Bacterial Infections in Patients with STAT1 Gain-of-Function Mutations

PURPOSES

STAT1 is a transduction and transcriptional regulator that functions within the classical JAK/STAT pathway. In addition to chronic mucocutaneous candidiasis, bacterial infections are a common occurrence in patients with STAT1 gain-of-function (GOF) mutations. These patients often exhibit skewing of B cell subsets; however, the impact of STAT1-GOF mutations on B cell-mediated humoral immunity remains largely unexplored. It is also unclear whether these patients with IgG within normal range require regular intravenous immunoglobulin (IVIG) therapy.

METHODS

Eleven patients (harboring nine different STAT1-GOF mutations) were enrolled. Reporter assays and immunoblot analyses were performed to confirm STAT1 mutations. Flow cytometry, deep sequencing, ELISA, and ELISpot were conducted to assess the impact of STAT1-GOF on humoral immunity.

RESULTS

All patients exhibited increased levels of phospho-STAT1 and total STAT1 protein, with two patients carrying novel mutations. In vitro assays showed that these two novel mutations were GOF mutations. Three patients with normal total IgG levels received regular IVIG infusions, resulting in effective control of bacterial infections. Four cases showed impaired affinity and specificity of pertussis toxin-specific antibodies, accompanied by reduced generation of class-switched memory B cells. Patients also had a disrupted immunoglobulin heavy chain (IGH) repertoire, coupled with a marked reduction in the somatic hypermutation frequency of switched Ig transcripts.

CONCLUSION

STAT1-GOF mutations disrupt B cell compartments and skew IGH characteristics, resulting in impaired affinity and antigen-specificity of antibodies and recurrent bacterial infections. Regular IVIG therapy can control these infections in patients, even those with normal total IgG levels.