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Talwar D, Hammer MF. SCN8A Epilepsy, Developmental Encephalopathy, and Related Disorders. Pediatr Neurol 2021; 122:76-83. [PMID: 34353676 DOI: 10.1016/j.pediatrneurol.2021.06.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 06/27/2021] [Accepted: 06/29/2021] [Indexed: 11/18/2022]
Abstract
Understanding the precise genetic -basis of disease is one of the critical developments in medicine in the twenty-first century. Genetic testing has revolutionized the diagnosis and treatment of neurological diseases in children. Whole-genome and whole-exome sequencing have particularly been useful in understanding the genetic basis of childhood epileptic encephalopathies characterized by early-onset seizures with significant developmental impairment and regression. In this review we describe the identification of a new epileptic encephalopathy caused by a de novo mutation in the SCN8A gene, which encodes for NaV1.6, a vital sodium channel in the central nervous system. SCN8A variants in patients with epilepsy result primarily in gain-of-function in Nav1.6 and hyperexcitability of neurons in the central nervous system. Following the original discovery in 2012 of a de novo mutation in a child with developmental and epileptic encephalopathy (DEE), more than 400 individuals with SCN8A-related disorders have been identified. Clinical manifestations range from movement disorders or intellectual disability only to severe DEE, which includes epileptic encephalopathy with intractable multivariate seizure types, developmental impairment and regression, intellectual disability, and other neurological manifestations. Gain-of-function of the Nav1.6 channel predicts effectiveness of sodium channel-blocking agents in the treatment of seizures, which has been corroborated by clinical experience. Nevertheless, treatment options remain limited and adverse effects are common. However, with the availability of a growing database of genetic and clinical data along with transfected cell lines and mouse models, more efficacious, targeted, and selective treatments may soon be feasible.
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Vetrini F, McKee S, Rosenfeld JA, Suri M, Lewis AM, Nugent KM, Roeder E, Littlejohn RO, Holder S, Zhu W, Alaimo JT, Graham B, Harris JM, Gibson JB, Pastore M, McBride KL, Komara M, Al-Gazali L, Al Shamsi A, Fanning EA, Wierenga KJ, Scott DA, Ben-Neriah Z, Meiner V, Cassuto H, Elpeleg O, Holder JL, Burrage LC, Seaver LH, Van Maldergem L, Mahida S, Soul JS, Marlatt M, Matyakhina L, Vogt J, Gold JA, Park SM, Varghese V, Lampe AK, Kumar A, Lees M, Holder-Espinasse M, McConnell V, Bernhard B, Blair E, Harrison V, Muzny DM, Gibbs RA, Elsea SH, Posey JE, Bi W, Lalani S, Xia F, Yang Y, Eng CM, Lupski JR, Liu P. De novo and inherited TCF20 pathogenic variants are associated with intellectual disability, dysmorphic features, hypotonia, and neurological impairments with similarities to Smith-Magenis syndrome. Genome Med 2019; 11:12. [PMID: 30819258 PMCID: PMC6393995 DOI: 10.1186/s13073-019-0623-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 02/15/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity). METHODS Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes. RESULTS We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances. CONCLUSIONS TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.
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Yang J, Li X, Xu D. Research Progress on the Involvement of ANGPTL4 and Loss-of-Function Variants in Lipid Metabolism and Coronary Heart Disease: Is the "Prime Time" of ANGPTL4-Targeted Therapy for Coronary Heart Disease Approaching? Cardiovasc Drugs Ther 2020; 35:467-477. [PMID: 32500296 DOI: 10.1007/s10557-020-07001-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Multiple genetic studies have confirmed the definitive link among the loss-of-function variants of angiogenin-like protein 4 (ANGPTL4), significantly decreased plasma triglyceride (TG) levels, and reduced risk of coronary heart disease (CHD). The potential therapeutic effect of ANGPTL4 on dyslipidemia and CHD has been widely studied. OBJECTIVE This review provides a detailed introduction to the research progress on the involvement of ANGPTL4 in lipid metabolism and atherosclerosis and evaluates the efficacy and safety of ANGPTL4 as a therapeutic target for CHD. RELEVANT FINDINGS By inhibiting lipoprotein lipase (LPL) activity, ANGPTL4 plays a vital role in the regulation of lipid metabolism and energy balance. However, the role of ANGPTL4 in regulating lipid metabolism is tissue-specific. ANGPTL4 acts as a locally released LPL inhibitor in the heart, skeletal muscle and small intestine, while ANGPTL4 derived from liver and adipose tissue mainly acts as an endocrine factor that regulates systemic lipid metabolism. As a multifunctional protein, ANGPTL4 also inhibits the formation of foam cells in macrophages, exerting an anti-atherogenic role. The function of ANGPTL4 in endothelial cells is still uncertain. The safety of ANGPTL4 monoclonal antibodies requires further evaluation due to their potential adverse effects. CONCLUSION The biological characteristics of ANGPTL4 are much more complex than those demonstrated by genetic studies. Future studies must elucidate how to effectively reduce the risk of CHD while avoiding potential atherogenic effects and other complications before the "prime time" of ANGPTL4-targeted therapy arrives.
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Li J, Lin H, Hou R, Shen J, Li X, Xing J, He F, Wu X, Zhao X, Sun L, Fan X, Niu X, Liu Y, Liu R, An P, Qu T, Chang W, Wang Q, Zhou L, Li J, Wang Z, Jiao J, Wang Y, Wang G, Liang N, Liang J, Liang Y, Hou H, Shi Y, Yang X, Li J, Dang E, Yin G, Yang X, Zhang G, Gao Q, Fang X, Li X, Zhang K. Multi-omics study in monozygotic twins confirm the contribution of de novo mutation to psoriasis. J Autoimmun 2019; 106:102349. [PMID: 31629629 DOI: 10.1016/j.jaut.2019.102349] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 10/03/2019] [Accepted: 10/07/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND Genome-wide association studies have identified over 120 risk loci for psoriasis. However, most of the variations are located in non-coding region with high frequency and small effect size. Pathogenetic variants are rarely reported except HLA-C*0602 with the odds ratio being approximately 4.0 in Chinese population. Although rare variations still account for a small proportion of phenotypic variances in complex diseases, their effect on phenotypes is large. Recently, more and more studies focus on the low-frequency functional variants and have achieved a certain amount of success. METHOD Whole genome sequencing and sanger sequencing was performed on 8 MZ twin pairs discordant for psoriasis to scan and verified the de novo mutations (DNMs). Additionally, 665 individuals with about 20 years' medical history versus 2054 healthy controls and two published large population studies which had about 8 years' medical history (including 10,727 cases versus 10,582 controls) were applied to validate the enrichment of rare damaging mutations in two DNMs genes. Besides, to verify the pathogenicity of candidate DNM in C3, RNA-sequencing for CD4+, CD8+ T cells of twins and lesion, non-lesion skin of psoriasis patients were carried out. Meanwhile, the enzyme-linked immunosorbent assay kit was used to detect the level of C3, C3b in the supernatant of peripheral blood. RESULT A total of 27 DNMs between co-twins were identified. We found six of eight twins carry HLA-C∗0602 allele which have large effects on psoriasis. And it is interesting that a missense mutation in SPRED1 and a splice region mutation in C3 are found in the psoriasis individuals in the other two MZ twin pairs without carrying HLA-C*0602 allele. In the replication stage, we found 2 loss-of-function (LOF) variants of C3 only in 665 cases with about 20 years' medical history and gene-wise analysis in 665 cases and 2054 controls showed that the rare missense mutations in C3 were enriched in cases (OR = 1.91, P = 0.0028). We further scanned the LOF mutations of C3 in two published studies (about 8 years' medical history), and found one LOF mutation in the case without carrying HLA-C*0602. In the individual with DNM in C3, RNA sequencing showed the expression level of C3 in skin was significant higher than healthy samples in public database (TPM fold change = 1.40, P = 0.000181) and ELISA showed protein C3 in peripheral blood was higher (~2.2-fold difference) than the other samples of twins without DNM in C3. CONCLUSION To the best of our knowledge, this is the first report that DNM in C3 is the likely pathological mutations, and it provided a better understanding of the genetic etiology of psoriasis and additional treatments for this disease.
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Research Support, Non-U.S. Gov't |
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Pio MG, Siffo S, Scheps KG, Molina MF, Adrover E, Abelleyro MM, Rivolta CM, Targovnik HM. Curating the gnomAD database: Report of novel variants in the thyrogobulin gene using in silico bioinformatics algorithms. Mol Cell Endocrinol 2021; 534:111359. [PMID: 34119605 DOI: 10.1016/j.mce.2021.111359] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 01/09/2023]
Abstract
Thyroglobulin (TG) is a large glycosylated protein of 2767 amino acids, secreted by the thyrocytes into the follicular lumen. It plays an essential role in the process of thyroid hormone synthesis. TG gene variants lead to permanent congenital hypothyroidism. In the present work, we report a detailed population and bioinformatic prediction analyses of the TG variants indexed in the Genome Aggregation Database (gnomAD). The results showed a clear predominance of nonsense variants in the European (Finnish), European (Non-Finnish) and Ashkenazi Jewish ethnic groups, whereas the splice site variants predominate in South Asian and African/African-American populations. In total, 282 novel TG variants were described (47 missense involving the wild-type cysteine residues, 177 missense located in the ChEL domain and 58 splice site variants) which were not reported in the literature and that would have deleterious effects in prediction programs. In the gnomAD population, the estimated prevalence of heterozygous carriers of the potentially damaging variants was 1:320. In conclusion, we provide an updated and curated reference source for the diagnosis of thyroid disease, mainly to congenital hypothyroidism due to TG deficiency. The identification and characterization of TG variants is undoubtedly a valuable approach to study the TG structure/function relations and an important tool for clinical diagnosis and genetic counseling.
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Zech M, Brunet T, Škorvánek M, Blaschek A, Vill K, Hanker B, Hüning I, Haň V, Došekova P, Gdovinová Z, Alhaddad B, Berutti R, Strom TM, Růžička E, Kamsteeg EJ, van der Smagt JJ, Wagner M, Jech R, Winkelmann J. Recessive null-allele variants in MAG associated with spastic ataxia, nystagmus, neuropathy, and dystonia. Parkinsonism Relat Disord 2020; 77:70-75. [PMID: 32629324 DOI: 10.1016/j.parkreldis.2020.06.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/08/2020] [Accepted: 06/23/2020] [Indexed: 02/05/2023]
Abstract
INTRODUCTION The gene encoding myelin-associated glycoprotein (MAG) has been implicated in autosomal-recessive spastic paraplegia type 75. To date, only four families with biallelic missense variants in MAG have been reported. The genotypic and phenotypic spectrum of MAG-associated disease awaits further elucidation. METHODS Four unrelated patients with complex neurologic conditions underwent whole-exome sequencing within research or diagnostic settings. Following determination of the underlying genetic defects, in-depth phenotyping and literature review were performed. RESULTS In all case subjects, we detected ultra-rare homozygous or compound heterozygous variants in MAG. The observed nonsense (c.693C > A [p.Tyr231*], c.980G > A [p.Trp327*], c.1126C > T [p.Gln376*], and 1522C > T [p.Arg508*]) and frameshift (c.517_521dupAGCTG [p.Trp174*]) alleles were predicted to result in premature termination of protein translation. Affected patients presented with variable combinations of psychomotor delay, ataxia, eye movement abnormalities, spasticity, dystonia, and neuropathic symptoms. Cerebellar signs, nystagmus, and pyramidal tract dysfunction emerged as unifying features in the majority of MAG-mutated individuals identified to date. CONCLUSIONS Our study is the first to describe biallelic null variants in MAG, confirming that loss of myelin-associated glycoprotein causes severe infancy-onset disease with central and peripheral nervous system involvement.
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Cuinat S, Bézieau S, Deb W, Mercier S, Vignard V, Isidor B, Küry S, Ebstein F. Understanding neurodevelopmental proteasomopathies as new rare disease entities: A review of current concepts, molecular biomarkers, and perspectives. Genes Dis 2024; 11:101130. [PMID: 39220754 PMCID: PMC11364055 DOI: 10.1016/j.gendis.2023.101130] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/30/2023] [Accepted: 08/19/2023] [Indexed: 09/04/2024] Open
Abstract
The recent advances in high throughput sequencing technology have drastically changed the practice of medical diagnosis, allowing for rapid identification of hundreds of genes causing human diseases. This unprecedented progress has made clear that most forms of intellectual disability that affect more than 3% of individuals worldwide are monogenic diseases. Strikingly, a substantial fraction of the mendelian forms of intellectual disability is associated with genes related to the ubiquitin-proteasome system, a highly conserved pathway made up of approximately 1200 genes involved in the regulation of protein homeostasis. Within this group is currently emerging a new class of neurodevelopmental disorders specifically caused by proteasome pathogenic variants which we propose to designate "neurodevelopmental proteasomopathies". Besides cognitive impairment, these diseases are typically associated with a series of syndromic clinical manifestations, among which facial dysmorphism, motor delay, and failure to thrive are the most prominent ones. While recent efforts have been made to uncover the effects exerted by proteasome variants on cell and tissue landscapes, the molecular pathogenesis of neurodevelopmental proteasomopathies remains ill-defined. In this review, we discuss the cellular changes typically induced by genomic alterations in proteasome genes and explore their relevance as biomarkers for the diagnosis, management, and potential treatment of these new rare disease entities.
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Cohen BM, Singh T, Öngür D, Konstantin GE, Gardner ME. Clinical phenotypes of five patients with psychotic disorders carrying rare schizophrenia-associated loss-of-function variants. Schizophr Res 2022; 250:100-103. [PMID: 36399898 DOI: 10.1016/j.schres.2022.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 09/30/2022] [Accepted: 11/05/2022] [Indexed: 11/17/2022]
Abstract
The Schizophrenia Exome Meta-Analysis (SCHEMA) consortium identified 10 genes in which loss-of-function (LoF) variants are highly associated with schizophrenia (SZ). In a well-characterized sample of 988 patients with psychotic disorders, we investigated whether patients bearing a SCHEMA variant presented with unusual or unique signs, symptoms, or course of illness. We identified 5 patients who carried a LoF variant in a SCHEMA gene, each in a different gene. None of the patients with a SCHEMA variant had unique symptoms. However, compared to the average of patients in the sample, all of the patients with a SCHEMA variant had earlier onset of any mental illness and more hospitalizations. Also, among SCHEMA carriers, 80 % were treated with clozapine, 60 % with ECT, all with either clozapine or ECT and 40 % with both clozapine and ECT, compared to only 2 % treated with clozapine and 18 % treated with ECT in the comparison group of patients without SCHEMA variants. All 5 patients with a SCHEMA variant had polysubstance abuse, and all had attempted suicide. Fewer than half had such presentations in the group without SCHEMA variants. In this small sample, SCHEMA variants appear to be associated with earlier onset, less favorable response to standard first-line treatments, and more severe illness, but not unique presentations of illness.
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Loss-of-function variants in FSIP1 identified by targeted sequencing are associated with one particular subtype of mucosal melanoma. Gene 2020; 759:144964. [PMID: 32717308 DOI: 10.1016/j.gene.2020.144964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/04/2020] [Accepted: 07/13/2020] [Indexed: 12/30/2022]
Abstract
BACKGROUND Mucosal melanoma is a tumor caused by the malignant transformation of pigment-producing cells and can arise from any mucosal tissue where melanocytes are present. Due to its rarity, the mucosal melanoma subtype is poorly described, and its genetic characteristics are infrequently studied. The discovery or confirmation of new mucosal melanoma susceptibility genes will provide important insights for the study of its pathogenesis. MATERIALS AND METHODS We performed deep targeted sequencing of 100 previously reported melanoma-related genes in 39 mucosal melanoma samples and a gene-level loss-of-function (LOF) variant enrichment analysis for mucosal melanoma from different incidence sites. RESULTS We detected 7,589 variants in these samples, and 484 were LOF variants (gain or loss of a stop codon, missense, and splice site). Four different gene-level enrichment analyses revealed that FSIP1 (fibrous sheath interacting protein 1) is a susceptibility gene for oral mucosal melanoma (OR = 0.33, PChi = 4.05 × 10-2, Pburden = 3.06 × 10-2, Pskat = 3.01 × 10-2, Pskato = 3.01 × 10-2), whereas the different methods did not detect a significant susceptibility gene for the other subtypes. CONCLUSIONS In our study, a susceptibility gene for oral mucosal melanoma was confirmed in a Chinese Han population, and these findings contribute to a better genetic understanding of mucosal melanoma of different subtypes.
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Chen H, Zhang S, Sun Y, Chen J, Yuan K, Zhang Y, Yang X, Lin X, Chen R. Novel pathogenic NPR2 variants in short stature patients and the therapeutic response to rhGH. Orphanet J Rare Dis 2023; 18:221. [PMID: 37501190 PMCID: PMC10375756 DOI: 10.1186/s13023-023-02757-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 06/04/2023] [Indexed: 07/29/2023] Open
Abstract
OBJECTIVE Heterozygous loss-of-function variants in the NPR2 gene cause short stature with nonspecific skeletal abnormalities and account for about 2 ~ 6% of idiopathic short stature. This study aimed to analyze and identify pathogenic variants in the NPR2 gene and explore the therapeutic response to recombinant growth hormone (rhGH). METHODS NPR2 was sequenced in three Chinese Han patients with short stature via exome sequencing. In vitro functional experiments, homology modeling and molecular docking analysis of variants were performed to examine putative protein changes and the pathogenicity of the variants. RESULT Three patients received rhGH therapy for two years, and two NPR2 heterozygous variants were identified in three unrelated cases: c.1579 C > T,p.Leu527Phe in patient 1 and c.2842dupC,p.His948Profs*5 in patient 2. Subsequently, a small gene model was constructed, and transcriptional analysis of the synonymous variant (c.2643G > A) was performed in patient 3, which revealed the deletion of exon 17 and the premature formation of a stop codon (p.His840Gln*). Functional studies showed that both NPR2 variants, His948Profs*5 and His840Gln*, failed to produce cGMP in the homozygous state. Furthermore, the Leu527Phe variant of NPR2 was almost unresponsive to the stimulatory effect of ATP on CNP-dependent guanylyl cyclase activity. This loss of response to ATP has not been previously reported. The average age of patients at the start of treatment was 6.5 ± 1.8 years old, and their height increased by 1.59 ± 0.1 standard deviation score after 2 years of treatment. CONCLUSION In this report, two novel variants in NPR2 gene were described. Our findings broaden the genotypic spectrum of NPR2 variants in individuals with short stature and provid insights into the efficacy of rhGH in these patients.
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Molina MF, Pio MG, Scheps KG, Adrover E, Abelleyro MM, Targovnik HM, Rivolta CM. Curating the gnomAD database: Report of novel variants in the thyroid peroxidase gene using in silico bioinformatics algorithms and a literature review. Mol Cell Endocrinol 2022; 558:111748. [PMID: 35995307 DOI: 10.1016/j.mce.2022.111748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/31/2022] [Accepted: 08/01/2022] [Indexed: 12/15/2022]
Abstract
Thyroid peroxidase (TPO) is a membrane-bound glycoprotein located at the apical side of the thyroid follicular cells that catalyzes both iodination and coupling of iodotyrosine residues within the thyroglobulin molecule, leading to the synthesis of thyroid hormone. Variants in TPO cause congenital hypothyroidism (CH) by iodide organification defect and are commonly inherited in an autosomal recessive fashion. In the present work, we report a detailed population analysis and bioinformatic prediction of the TPO variants indexed in the Genome Aggregation Database (gnomAD) v2.1.1. The proportion of missense cysteine variants and nonsense, frameshift, and splice acceptor/donor variants were analyzed in each ethnic group (European (Non-Finnish), European (Finnish), African/African Americans, Latino/Admixed American, East Asian, South Asian, Ashkenazi Jewish, Other). The results showed a clear predominance of frameshift variants in the East Asian (82%) and European (Finnish) (75%) population, whereas the splice site variants predominate in African/African Americans (99.46%), Other (96%), Latino/Admixed American (94%), South Asian (86%), European (Non-Finnish) (56%) and Ashkenazi Jewish (56%) populations. The analysis of the distribution of the variants indexed in gnomAD v2.1.1 database revealed that most missense variants identified in the An peroxidase domain map in exon 8, followed by exons 11, 7 and 9, and finally in descending order by exons 10, 6, 12 and 5. In total, 183 novel TPO variants were described (13 missense cysteine's variants, 158 missense variants involving the An peroxidase domain and 12 splicing acceptor or donor sites variants) which were not reported in the literature and that would have deleterious effects on prediction programs. In the gnomAD v2.1.1 population, the estimated prevalence of heterozygous carriers of the potentially damaging variants was 1:77. In conclusion, we provide an updated and curated reference source of new TPO variants for application in clinical diagnosis and genetic counseling. Also, this work contributes to elucidating the molecular basis of CH associated with TPO defects.
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Huang Y, Xiang Z, Xiang Y, Pan H, He M, Guo Z, Kanca O, Liu C, Zhang Z, Zhan H, Wang Y, Bai QR, Bellen HJ, Wang H, Bian S, Mao X. Biallelic MED16 variants disrupt neural development and lead to an intellectual disability syndrome. J Genet Genomics 2025:S1673-8527(25)00113-4. [PMID: 40254158 DOI: 10.1016/j.jgg.2025.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2024] [Revised: 04/03/2025] [Accepted: 04/06/2025] [Indexed: 04/22/2025]
Abstract
Mediator Complex Subunit 16 (MED16, MIM: 604062) is a member of the Mediator complex which controls many aspects of transcriptional activity in all eukaryotes. Here, we report two individuals from a non-consanguineous family with biallelic variants in MED16 identified by exome sequencing. The affected individuals present with global developmental delay, intellectual disability, and dysmorphisms. To assess the pathogenicity of the variants, functional studies were performed in Drosophila and patient-derived cells. The fly ortholog med16 is expressed in neurons and some glia of the developing central nervous system (CNS). Loss of med16 leads to a reduction in eclosion and lifespan, as well as impaired synaptic transmission. In neurons differentiated from the patient-derived induced pluripotent stem cells (iPSCs), the neurite outgrowth is impaired and rescued by expression of exogenous MED16. The patient-associated variants behave as loss-of-function (LoF) alleles in flies and iPSCs. Additionally, the transcription of genes related to neuronal maturation and function is preferentially altered in patient cells relative to differentiated H9 controls. In summary, our findings support that MED16 is important for appropriate development and function, and that biallelic MED16 variants cause a neurodevelopmental disease.
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Zeb A, Yang M, Ahmad N, Zhang H, Shah W, Khan K, Uddin M, Mansoor A, Rahim F, Hussain A, Ali I, Abbas T, Zubair M, Khan I, Shi Q. Novel biallelic ADCY10 variants cause asthenozoospermia with excessive residual cytoplasm and hydronephrosis in humans. Reprod Biomed Online 2025; 50:104481. [PMID: 39891992 DOI: 10.1016/j.rbmo.2024.104481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 08/10/2024] [Accepted: 09/30/2024] [Indexed: 02/03/2025]
Abstract
RESEARCH QUESTION Could the novel mutations in ADCY10 cause asthenozoospermia and absorptive hypercalciuria in humans, and the potential pathogenesis? DESIGN Whole-exome sequencing and Sanger sequencing were conducted to identify potential pathogenic variants in two unrelated Pakistani families. Reverse transcription polymerase chain reaction was utilized to assess the mutation effect on mRNA levels in the patients. Transmission electron microscopy and scanning electron microscopy were performed to examine the sperm flagellar ultrastructure. Western blot and immunofluorescence assays were performed to evaluate the expression and localization of ADCY10 and other axonemal components. RESULTS Three novel ADCY10 variants were identified in two unrelated Pakistani families. Patient 1 (P1) and P2 from Family 1 carried compound heterozygous mutation c.2902C>T (p. Arg968*) and c.4286+1G>T, and P3 and P4 from Family 2 carried homozygous mutation c.436+2T>G. These patients suffered from male infertility with compromised sperm motility and hydronephrosis with kidney stones. No ADCY10 mRNA and ADCY10 protein were detected in the blood and sperm lysate of the patients. Morphological analyses revealed obvious mid-piece defects along with head anomalies in the patients' spermatozoa. Transmission electron microscopy and immunofluorescence assay showed excessive residual cytoplasm in the mitochondrial sheath and misarranged mitochondrial sheath structures in the patients, indicating a novel role of ADCY10 in regulating the proper organization of the mitochondrial sheath. CONCLUSIONS These results indicate that ADCY10 is an important factor for maintaining the proper structure of the mitochondrial sheath and motility of spermatozoa, which extends the phenotype spectrum of ADCY10 loss-of-function mutations in humans.
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Ebstein F, Latypova X, Hung KYS, Prado MA, Lee BH, Möller S, Zieba BA, Florenceau L, Vignard V, Poirier L, Moroni I, Dubucs C, Chassaing N, Horvath J, Prokisch H, Küry S, Bézieau S, Paulo JA, Finley D, Krüger E, Ghezzi D, Isidor B. Biallelic USP14 variants cause a syndromic neurodevelopmental disorder. Genet Med 2024; 26:101120. [PMID: 38469793 PMCID: PMC11241549 DOI: 10.1016/j.gim.2024.101120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 03/13/2024] Open
Abstract
PURPOSE Imbalances in protein homeostasis affect human brain development, with the ubiquitin-proteasome system (UPS) and autophagy playing crucial roles in neurodevelopmental disorders (NDD). This study explores the impact of biallelic USP14 variants on neurodevelopment, focusing on its role as a key hub connecting UPS and autophagy. METHODS Here, we identified biallelic USP14 variants in 4 individuals from 3 unrelated families: 1 fetus, a newborn with a syndromic NDD and 2 siblings affected by a progressive neurological disease. Specifically, the 2 siblings from the latter family carried 2 compound heterozygous variants c.8T>C p.(Leu3Pro) and c.988C>T p.(Arg330∗), whereas the fetus had a homozygous frameshift c.899_902del p.(Lys300Serfs∗24) variant, and the newborn patient harbored a homozygous frameshift c.233_236del p.(Leu78Glnfs∗11) variant. Functional studies were conducted using sodium dodecyl-sulfate polyacrylamide gel electrophoresis, western blotting, and mass spectrometry analyses in both patient-derived and CRISPR-Cas9-generated cells. RESULTS Our investigations indicated that the USP14 variants correlated with reduced N-terminal methionine excision, along with profound alterations in proteasome, autophagy, and mitophagy activities. CONCLUSION Biallelic USP14 variants in NDD patients perturbed protein degradation pathways, potentially contributing to disorder etiology. Altered UPS, autophagy, and mitophagy activities underscore the intricate interplay, elucidating their significance in maintaining proper protein homeostasis during brain development.
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Zhao L, Li Q, Kuang Y, Xu P, Sun X, Meng Q, Wang W, Zeng Y, Chen B, Fu J, Dong J, Zhu J, Luo Y, Gu H, Li C, Li C, Wu L, Mao X, Fan H, Liu R, Zhang Z, Li Q, Du J, He L, Jin L, Wang L, Sang Q. Heterozygous loss-of-function variants in LHX8 cause female infertility characterized by oocyte maturation arrest. Genet Med 2022; 24:2274-2284. [PMID: 36029299 DOI: 10.1016/j.gim.2022.07.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/26/2022] Open
Abstract
PURPOSE The genetic causes of oocyte maturation arrest leading to female infertility are largely unknown, and no population-based genetic analysis has been applied in cohorts of patients with infertility. We aimed to identify novel pathogenic genes causing oocyte maturation arrest by using a gene-based burden test. METHODS Through comparison of exome sequencing data from 716 females with infertility characterized by oocyte maturation arrest and 3539 controls, we performed a gene-based burden test and identified a novel pathogenic gene LHX8. Splicing event was evaluated using a minigene assay, expression of LHX8 protein was assessed in HeLa cells, and nuclear subcellular localization was determined in both HeLa cells and mouse oocytes. RESULTS A total of 5 heterozygous loss-of-function LHX8 variants were identified from 6 independent families (c.389+1G>T, c.412C>T [p.Arg138∗], c.282C>A [p.Cys94∗]; c.257dup [p.Tyr86∗]; and c.180del, [p.Ser61Profs∗30]). All the identified variants in LHX8 produced truncated LHX8 protein and resulted in loss of LHX8 nuclear localization in both HeLa cells and mouse oocytes. CONCLUSION By combining genetic evidence and functional evaluations, we identified a novel pathogenic gene LHX8 and established the causative relationship between LHX8 haploinsufficiency and female infertility characterized by oocyte maturation arrest.
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Ho PJ, Lim EH, Hartman M, Wong FY, Li J. Breast cancer risk stratification using genetic and non-genetic risk assessment tools for 246,142 women in the UK Biobank. Genet Med 2023; 25:100917. [PMID: 37334786 DOI: 10.1016/j.gim.2023.100917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 06/20/2023] Open
Abstract
PURPOSE The benefit of using individual risk prediction tools to identify high-risk individuals for breast cancer (BC) screening is uncertain, despite the personalized approach of risk-based screening. METHODS We studied the overlap of predicted high-risk individuals among 246,142 women enrolled in the UK Biobank. Risk predictors assessed include the Gail model (Gail), BC family history (FH, binary), BC polygenic risk score (PRS), and presence of loss-of-function (LoF) variants in BC predisposition genes. Youden J-index was used to select optimal thresholds for defining high-risk. RESULTS In total, 147,399 were considered at high risk for developing BC within the next 2 years by at least 1 of the 4 risk prediction tools examined (Gail2-year > 0.5%: 47%, PRS2-yea r > 0.7%: 30%, FH: 6%, and LoF: 1%); 92,851 (38%) were flagged by only 1 risk predictor. The overlap between individuals flagged as high-risk because of genetic (PRS) and Gail model risk factors was 30%. The best-performing combinatorial model comprises a union of high-risk women identified by PRS, FH, and, LoF (AUC2-year [95% CI]: 62.2 [60.8 to 63.6]). Assigning individual weights to each risk prediction tool increased discriminatory ability. CONCLUSION Risk-based BC screening may require a multipronged approach that includes PRS, predisposition genes, FH, and other recognized risk factors.
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