CHARGE syndrome associated with (I1460Rfs*15) frameshift mutation of CHD7 gene in a patient with arteria lusoria and horseshoe kidney

Spectrum of congenital anomalies of the kidney and urinary tract (CAKUT) including renal parenchymal malformations during fetal life and the implementation of prenatal exome sequencing (WES)

OBJECTIVES AND BACKGROUND

Congenital malformations of the kidney and urinary tract (CAKUT) have a prevalence of 4-60 in 10,000 livebirths and constitute for 40-50% of all end stage pediatric kidney disease. CAKUT can have a genetic background due to monogenetic inherited disease, such as PKD or ciliopathies. They can also be found in combination with extra-renal findings as part of a syndrome. Upon detection of genitourinary malformations during the fetal anomaly scan the question arises if further genetic testing is required. The purpose of this study was to determine the phenotypic presentation of CAKUT cases and the results of exome analysis (WES).

METHODS

This is a retrospective analysis of 63 fetal cases with a diagnosis of CAKUT or DSD at a single center between August 2018 and December 2022.

RESULTS

A total of 63 cases (5.6%) out of 1123 matched CAKUT phenotypes including renal parenchyma malformations. In 15 out of 63 WES analysis a pathogenic variant was detected (23.8%). In fetuses with isolated CAKUT the rate of detecting a pathogenic variant on exome sequencing was five out of 44 (11.4%). Ten out of 19 fetuses (52.6%) that displayed extra-renal findings in combination with CAKUT were diagnosed with a pathogenic variant.

CONCLUSIONS

WES provides an increase in diagnosing pathogenic variants in cases of prenatally detected CAKUT. Especially in fetuses with extra-renal malformations, WES facilitates a gain in information on the fetal genotype to enhance prenatal counselling and management.

A novel CHD7 variant in a chinese family with CHARGE syndrome

OBJECTIVE

CHARGE syndrome is a rare autosomal dominant (AD) multi-system disorder with a broad and variable clinical manifestation and occurs in approximately 1/10,000 newborns in the world. Mutations in the CHD7 gene are the genetic cause of over 90% of patients with typical CHARGE syndrome. The present study reported a novel variant in the CHD7 gene in a Chinese family with an abnormal fetus.

METHODS

Routine prenatal ultrasound screening showed fetal heart abnormality and left foot varus. Chromosomal microarray analysis (CMA) and fetus-parent whole-exome sequencing (trio-WES) were performed to determine the genetic cause of the fetus. The candidate variant was further verified using Sanger sequencing.

RESULTS

CMA analysis revealed normal results. However, WES analysis identified a de novo heterozygous variant of c.2919_2922del (NM_017780.4) on exon 11 of CHD7 gene, resulting in a premature truncation of the CHD7 protein (p.Gly975*). The variant was classified as Pathogenic (PVS1 + PS2_Moderate + PM2_Supporting) based on the ACMG guidelines. Combined with the clinical phenotype of fetal heart abnormalities, it was confirmed CHARGE syndrome.

CONCLUSION

We identified a novel heterozygous variant c.2919_2922del in CHD7 of a Chinese fetus with CHARGE syndrome, enriching the genotype-phenotype spectrum of CHD7. These results suggest that genetic testing could help facilitate prenatal diagnosis of CHARGE syndrome, thus promoting the appropriate genetic counseling.

Digenic CHD7 and SMCHD1 inheritance Unveils phenotypic variability in a family mainly presenting with hypogonadotropic hypogonadism

Objectives

CHARGE syndrome is a congenital hereditary condition involving multiple systems. Patients are easily misdiagnosed with idiopathic hypogonadotropic hypogonadism (IHH) due to the overlap of clinical manifestations. An accurate clinical diagnosis remains challenging when the predominant clinical manifestation resembles hypogonadotropic hypogonadism.

Methods

This original research is conducted based on the genetic finding and analysis of clinical cases. Whole-exome sequencing (WES) and in-silico analyse were performed on two sisters to investigate the pathogenesis in this family. Homology modelling was conducted to evaluate structural changes in the variants.

Results

WES and Sanger sequencing revealed two siblings carrying a nonsense mutation (NM_017780.4: c.115C > T) in exon 2 of CHD7 inherited from a mildly affected mother and a missense mutation (NM_015295.3: c.2582T > C) in exon 20 of SMCHD1 inherited from an asymptomatic father. The nonsense mutation in CHD7 was predicted to generate nonsense-mediated decay, whereas the missense mutation in SMCHD1 decreased protein stability.

Conclusions

We identified digenic CHD7 and SMCHD1 mutations in IHH-associated diseases for the first time and verified the synergistic role of oligogenic inheritance. It was also determined that WES is an effective tool for distinguishing diseases with overlapping features and establishing a molecular diagnosis for cases with digenic or oligogenic hereditary disorders, which is beneficial for timely treatment, and family genetic counseling.

Discovery of Novel Variants on the CHD7 Gene: A Case Series of CHARGE Syndrome

Background: CHARGE syndrome (CS) is a single-gene genetic disorder with multiple organ malformations caused by a variant of the chromodomain helicase DNA-binding protein 7 (CHD7) gene on chromosome 8q12.1. In this study, we aimed to investigate new variants that have emerged in these cases compared with typical CS and the relationship between the genes and phenotypes. Methods: Patients with suspected genetic diseases were subjected to Whole Exome Sequencing (WES) at a genetics laboratory in Guangzhou. The average sequencing coverage depth was >200 ×, and 96% was >20 ×. The variant interpretation was manipulated according to the American College of Medical Genetics (ACMG) guidelines. Molecular data on databases for ClinVar and CHD7 were also collected and collated. We reviewed the currently described CHD7 variants and analyzed the genetic variation and phenotypic heterogeneity. Results: Data of 12 patients with CS from four hospitals in China were collected. According to gestational age, most of them (8/12) were near-term babies with a lower birth weight than their peers, averaging 2.62 kg. In this study, the most common phenotypes were respiratory tract malformations (11/12), heart malformations (10/12), and central nervous system malformations (9/12). Two fetuses were confirmed to have brain or heart abnormalities during prenatal testing, while 10/12 were found to have abnormalities during prenatal testing. The maximum Acute Physiology and Chronic Health Evaluation (APACHE II) score at admission was 19, and the average was 11.58. Five variants in the CHD7 gene c.7012C > T (p.Q2338*), c.7868delC (p.P2623Rfs*16), c.5405-3C > G, c.6936 + 2T > C, and c.8077-2A > G) were novel and were located in exons 33, 36, and introns 25, 32, and 37, respectively. There may be a positive correlation between exon location and phenotype. Conclusion: Five novel variants were discovered. These expanded the mutational spectrum of the CHD7 gene and the phenotype of CS. There may be a correlation between the new mutation sites and the phenotype, which has some reference value for the evaluation of mutation sites.

Genetic Counseling and Management: The First Study to Report NIPT Findings in a Romanian Population

Background and Objectives: Non-invasive prenatal testing (NIPT) has been confirmed as the most accurate screening test for trisomies 21, 18, 13, sex chromosomes aneuploidies and several microdeletions. This study aimed to assess the accuracy of cell free DNA testing based on low-level whole-genome sequencing to screen for these chromosomal abnormalities and to evaluate the clinical performance of NIPT. Materials and Methods: 380 consecutive cases from a single genetic center, from Western Romania were included in this retrospective study. Cell-free nucleic acid extraction from maternal blood, DNA sequencing and analysis of sequenced regions were performed by BGI Hong Kong and Invitae USA to determine the risk of specific fetal chromosomal abnormalities. In high-risk cases the results were checked by direct analysis of fetal cells obtained by invasive methods: 6 chorionic villus sampling and 10 amniocenteses followed by combinations of QF-PCR, karyotyping and aCGH. Results: NIPT results indicated low risk in 95.76% of cases and high risk in 4.23%. Seven aneuploidies and one microdeletion were confirmed, the other results were found to be a false-positive. A gestational age of up to 22 weeks had no influence on fetal fraction. There were no significant differences in fetal fraction across the high and low risk groups. Conclusions: This is the first study in Romania to report the NIPT results. The confirmation rate was higher for autosomal aneuploidies compared to sex chromosome aneuploidies and microdeletions. All cases at risk for trisomy 21 were confirmed. Only one large fetal microdeletion detected by NIPT has been confirmed. False positive NIPT results, not confirmed by invasive methods, led to the decision to continue the pregnancy. The main limitation of the study is the small number of patients included. NIPT can be used as a screening method for all pregnancies, but in high-risk cases, an invasive confirmation test was performed.

Arteria lusoria: a trick of nature

Dysphagia has several typical causes. In this case report a young adult with difficulties in swallowing since childhood is diagnosed with a rare anatomical variation of the aortal branches.

Benefits of robotic devices in medical rehabilitation of a case with neurofibromatosis type1

The term neurofibromatosis (NF) describes a group of genetic disorders that primarily affect the cell growth of neural tissues. Three clinically and genetically distinct forms of neurofibromatosis have been described: neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and schwannomatosis. The inheritance pattern is autosomal dominant for all three types. We present the case of a 57 years old man, admitted to the Medical Rehabilitation Clinical Hospital Baile Felix, Romania, who was diagnosed with spastic tetraparesis, neurofibromatosis type 1, chronic viral hepatitis B and D, hypercholesterolemia, sarcopenia and osteoporosis. The objectives of the rehabilitation treatment were combating pain; preventing and correcting vicious postures at rest and during activity; maintaining or increasing joint mobility; increasing the mobility of the cervical and lumbar spine; decreasing spasticity; increasing strength of paralyzed muscles; improving motor control of paralyzed limbs; transfers re-education, gait re-education; improving breathing; improving ADLs; maintaining autonomy; gaining daily independence; prevention of recurrent complications and increasing the quality of life. The rehabilitation treatment was complex, performed over a period of 2 weeks and included various physiotherapy approaches, hydrokinetotherapy, massage, occupational therapy, robotic devices and virtual reality. It improved the patient's functional independence and quality of life. Innovations in information technology will refine and increase the efficiency, expertise and competence of medical rehabilitation, in order to ensure comfort for the patient and an appropriate and safe therapeutic approach. Keywords: neurofibromatosis, robotic devices, medical rehabilitation,

Heterogeneity in combined immunodeficiencies with associated or syndromic features (Review)

Primary immunodeficiencies are genetic diseases, mainly monogenic, that affect various components of the immune system and stages of the immune response. The category of combined immunodeficiencies with associated or syndromic features comprises over 70 clinical entities, characterized by heterogeneity of clinical presentation, mode of transmission, molecular, biological, mutational and immunological aspects. The mutational spectrum is wide, ranging from structural chromosomal abnormalities to gene mutations. The impact on the function of the proteins encoded by the genes involved is different; loss of function is most common, but situations with gain of function are also described. Most proteins have multiple functions and are components of several protein interaction networks. The pathophysiological mechanisms mainly involve: Missing enzymes, absent or non-functional proteins, abnormal DNA repair pathways, altered signal transduction, developmental arrest in immune differentiation, impairment of cell-to-cell and intracellular communications. Allelic heterogeneity, reduced penetrance and variable expressivity are genetic phenomena that cause diagnostic difficulties, especially since most are rare/very rare diseases, which is equivalent to delaying proper case management. Most primary immunodeficiencies are Mendelian diseases with X-linked or recessive inheritance, and molecular diagnosis allows the identification of family members at risk and the application of appropriate primary and secondary prevention measures in addition to the specific curative ones. In conclusion, recognizing heterogeneity and its sources is extremely important for current medical practice, but also for the theoretical value of improving biological and biomedical applications.

De novo 8p21.3→ p23.3 Duplication With t(4;8)(q35;p21.3) Translocation Associated With Mental Retardation, Autism Spectrum Disorder, and Congenital Heart Defects: Case Report With Literature Review

Duplications of chromosome 8p lead to rare genetic conditions characterized by variable phenotypes. 8p21 and 8p23 duplications were associated with mental retardation but only 8p23 duplication was associated with heart defects. 8p22→ p21.3 duplications were associated with an autism spectrum disorder in several cases. We present a rare case with a de novo duplication of the entire 8p21.3→ p23.3 region, documented by karyotype, FISH, and array CGH, with t(4;8)(q35;p21.3) translocation in a 7 years-old girl. She was referred for genetic counseling at the age of 20 months due to mild dysmorphic facial features, psychomotor retardation, and a noncyanotic heart defect. Another examination carried out at the age of 5 years, enabled the diagnosis of autism spectrum disorder and attention deficit hyperactivity disorder. Upon re-examination after two years she was diagnosed with autism spectrum disorder, attention deficit hyperactivity disorder, liminal intellect with cognitive disharmony, delay in psychomotor acquisitions, developmental language delay, an instrumental disorder, and motor coordination disorder. Cytogenetic analysis using GTG technique revealed the following karyotype: 46,XX,der(4),t(4;8)(q35;p21.3). The translocation of the duplicated 8pter region to the telomeric region 4q was confirmed by FISH analysis (DJ580L5 probe). Array CGH showed: arr[GRCh37]8p23.3p21.3(125733_22400607) × 3. It identified a terminal duplication, a 22.3 Mb copy number gain of chromosome 8p23.3-p21.3, between 125,733 and 22,400,607. In this case, there is a de novo duplication of a large chromosomal segment, which was translocated to chromosome 4q. Our report provides additional data regarding neuropsychiatric features in chromosome 8p duplication. The phenotypic consequences in our patient allow clinical-cytogenetic correlations and may also reveal candidate genes for the phenotypic features.

Rare splicing mutation in COL1A1 gene identified by whole exomes sequencing in a patient with osteogenesis imperfecta type I followed by prenatal diagnosis: A case report and review of the literature

BACKGROUND

Osteogenesis imperfecta (OI) is a rare disease characterized by increased bone fragility and predisposition to fractures, bone deformities and other major signs such as dentinogenesis imperfecta, blue sclera and deafness. Over 90% of OI cases are caused by mutations in the COL1A1 and COL1A2 genes and the inheritance is autosomal dominant.

METHODS

We present a case of a couple requesting genetic counseling, because the man was diagnosed with OI on a clinical and radiological basis and the woman was pregnant. Whole exomes sequencing (WES) was performed in order to identify the mutation (s), followed by prenatal diagnosis.

RESULTS

WES identified a rare splicing mutation c.1155 + 1G > C in the COL1A1 gene recognized to be pathogenic and subsequently confirmed by next generation sequencing. The carrier state of the mutation was excluded for the fetus, so the pregnancy was further pursued and a healthy baby was born at term.

CONCLUSIONS

WES is a new and effective technique for detecting pathogenic variants in monogenic diseases and it is preferable to use such a technique in diseases with genetic heterogeneity especially when time does not allow another time-consuming diagnostic technique such classical Sanger sequencing. WES offers possibility to expand the global spectrum of OI pathogenic variants enabling the diagnosis of the disease.