Clinical Genetics最新文献

Epilepsy, affecting approximately 50 million individuals worldwide, exhibits a genetic heritability of 32%. While several genes/loci associated with epilepsy have been identified through candidate and genome-wide association studies (GWAS), exploration of population-specific markers remains underexplored. We conducted the first GWAS in north Indian population (~1500 samples) to identify genetic variants/loci associated with epilepsy risk, validated using targeted next-generation sequencing (NGS). Our GWAS revealed 30 variants across seven loci associated with epilepsy risk, including six novel loci. Subtype analysis based on etiology and seizure types, identified 57 variants across 11 loci, 10 of which are novel. Gene-set analysis unveiled enrichment in genes associated with glutathione synthesis and recycling and regulation of dopaminergic neuron differentiation pivotal in epilepsy pathophysiology. Furthermore, PRS analysis revealed a significant genetic contribution to the epilepsy with an R² of 0.00573. Additionally, targeted NGS showed ~95% concordance with GSA genotypes. Our study highlights six novel loci rs17031055/4q31.3(DCHS2), rs73182224/3q27.2(DGKG), rs9322462/6q25.2(CNKSR3), rs75328617/8q24.23(RNU1-35P), rs2938010/10q26.13(CTBP2) and rs11652575/17p11.2(SLC5A10) associated with epilepsy risk. These findings offer valuable insights into the genetic landscape of epilepsy in the north Indian population, providing foundation for future exploratory studies.

Female infertility is a prevalent reproductive disorder with high genetic heterogeneity. Previous reports have demonstrated the causal role of biallelic pathogenic variants in the Subcortical Maternal Complex (SCMC) genes in female reproductive failure with some leading to infertility, early embryonic loss, and molar pregnancies, while others are compatible with live birth with and without multilocus imprinting disorders (MLID). Here, we report two deleterious protein-truncating variants, c.1326delG, p.Leu443Phefs*78 and c.2802_2803del, p.Arg935Metfs*15, in heterozygous state in the NLRP2 gene of a patient with primary infertility, four early miscarriages, and one failed attempt of intracytoplasmic sperm injection. We show that the two variants mediate mRNA decay in EBV-transformed lymphoblastoid cells from the patient, lead to decreased NLRP2 protein levels, and alter NLRP2 interactions with other members of the SCMC in vitro. This study emphasizes the importance of performing clinical exomes for patients with recurrent reproductive failure and reporting their variants and reproductive histories to improve patient counseling.

An 11-year-old presented with bilateral renal cell carcinoma (RCC) with FH-deficient RCC confirmed by immunohistochemistry. WGS confirmed no coding variants but identified a rare intronic variant in FH (c.1391-269A>G). We illustrate how combined pathological and genomic investigations enabled a precise diagnosis of the underlying cause of an ultra-rare clinical presentation.

Spinal muscular atrophy 5q (5q SMA) is one of the most prevalent autosomal recessive disorders globally. The underlying cause of 5q SMA is attributed to variants in SMN1. Exon 7 of SMN1 is not detectable in major of probands with 5q SMA, and minor of probands have a combination of the deletion and an intragenic subtle variant in the second allele. From 1991 to 2023, DNA samples from 2796 probands representing unrelated families were analyzed at the Research Centre for Medical Genetics for the diagnosis of 5q SMA. The copy number of Exon 7 of SMN1 and SMN2 was determined for all probands by MLPA. Subsequently, direct automated Sanger sequencing was employed to perform intragenic subtle variant screenings in all 116 probands with one copy of Exon 7 of SMN1. The diagnosis of 5q SMA was confirmed in 1495 probands. Among the 41 probands with one copy of Exon 7 of SMN1 from the initial 116 tested, 24 intragenic subtle variants in SMN1/SMN2 were documented. The aim of this study was to identify and characterize intragenic subtle variants in SMN1 and analyze their relationship with clinical manifestations in probands with 5q SMA in the Russian cohort.

Collision of monoallelic MUTYH and POLE germline variants in a patient with adrenocortical carcinoma who achieved a strong response to immunotherapy.

Lateralized overgrowth (LO) is characterized by excessive growth of one side of the body compared to the other. LO can present as isolated (ILO) or within syndromes, like Beckwith-Wiedemann Spectrum (BWSp) and PIK3CA-related overgrowth spectrum (PROS). Currently, the diagnosis of LO relies on clinical evaluation and lacks a standardized method. In this study, we evaluated total body dual-energy X-ray absorptiometry (TB-DXA) as a potential tool for standardizing LO assessment. Patients with LO underwent both clinical evaluation and TB-DXA. TB-DXA data, including total mass, mass of the three main tissue components (adipose, muscle, and bone), total mass discrepancy ratio, relative tissue composition, and discrepancy of relative tissue composition were calculated and compared with clinical findings. Differences between affected regions and the contralateral side were assessed. A total of 46 patients (61% PROS, 24% BWSp, 15% ILO) were included in this study. TB-DXA detected overgrowth regions aligned with clinical evaluation in 91% of cases and was able to identify localized overgrowth even when clinically overlooked. Additionally, TB-DXA revealed differences in tissue composition between affected and unaffected regions for symmetrical body areas, with these differences varying by diagnostic subgroup. Different patterns of tissue composition overgrowth were observed among different conditions, with PROS predominantly showing adipose tissue overgrowth, while BWSp/ILO mainly osteo-muscular overgrowth. TB-DXA is an accurate, safe, and reproducible tool in the clinical setting providing an objective method for identifying and quantifying LO. It offers valuable guidance for clinicians in the diagnosis and management of LO.

CBFB encodes the core-binding factor β subunit, a small protein which heterodimerises with RUNX1-3 and activates transcription of genes important in bone development. Recently, five families with cleidocranial dysplasia (CCD) were identified harbouring presumed loss of function variants in CBFB. Prompted by a multidisciplinary team review of an affected mother and daughter from the 100 000 Genomes Project with genetically unsolved CCD, we inspected read alignments and identified a deletion-inversion-deletion that removes the first two exons of CBFB. This cryptic variant comprised interlinked deletions of 1310 bp and 1935 bp and had remained undetected by both array-CGH and the Canvas algorithm. The rearrangement was likely mediated by a palindromic AluSx repeat < 1 kb from the transcriptional start site. Due to high GC content and repeats, reduced read depth is observed at one of the breakpoints. Although the clinical presentation of CBFB-related CCD appears to be very similar to RUNX2-related CCD, our patients were of normal stature. The mild developmental delay observed in previously reported cases of CBFB-related CCD was not observed. In conclusion, our data strengthens the evidence linking aberrations of the core-binding factor complex to CCD and extends the mutational spectrum of pathogenic variants.

Proprotein convertase 1/3 (PC1/3), encoded by PCSK1, is expressed in neuronal and endocrine cell types, where it activates a number of protein precursors that play roles in energy homeostasis. Biallelic PCSK1 loss-of-function mutations cause a polyendocrinopathy; a total of 34 patients were reported. An infant with congenital malabsorptive diarrhea of all carbohydrates underwent exome sequencing (ES), with particular consideration of PC1/3 deficiency, but no mutations were found. The onset of obesity in the second year of life increased suspicion of PC1/3 deficiency in the proband, as well as in his equally affected cousin. Transcript analysis revealed minor amounts of an aberrant PCSK1 transcript containing intron 9 sequence and encoding a premature stop codon (p.Pro400Valfs*35). A deep intronic PCSK1 variant, NG_021161.1(NM_000439.5):c.1196+2681T>A, was found to segregate in the proband's family with the disease. A minigene approach demonstrated that the identified deep-intronic variant underlies pseudo-exon inclusion of the intron 9 sequence in the transcript. The characteristic phenotype of PC1/3 deficiency might require extended genetic testing to make a timely diagnosis.

Adult patients with undiagnosed genetic disorders suffer most from diagnostic delay and seldom appear in cohort studies investigating the diagnostic yield in medical genetic clinical practice. Here we present the results of the diagnostic activity performed in a referral center on 654 consecutive, unselected adult subjects presenting with molecularly unsolved conditions. More than 50% of the referred individuals were affected by syndromic or isolated intellectual disability. Different molecular approaches, including clinical/whole exome sequencing (CES/WES), chromosomal microarray analysis (CMA), and/or targeted gene or gene panel sequencing were used to analyze patients' DNA. Definitive diagnosis was obtained in over 30% of individuals. The most sensitive methodology was CES/WES, which allowed us to reach a diagnosis in over 50% of the 162 solved cases. Despite the great variety of clinical presentations, our results represent a reliable picture of the "real world" daily routine in an outpatient medical genetics clinic dedicated to diagnostic activity, and contribute to better understand the great value of a definitive molecular diagnosis in adults, either for the affected individuals and their families. This retrospective analysis demonstrates the importance of adopting a genomic-first approach within the diagnostic process for adults affected with unsolved rare conditions.

To evaluate the diagnostic yield of prenatal exome sequencing (pES) in fetuses with structural anomalies detected by prenatal ultrasound in a consanguineous population. This was a prospective study of 244 anomalous fetuses from unrelated consanguineous Egyptian families. Detailed phenotyping was performed throughout pregnancy and postnatally, and pES data analysis was conducted. Genetic variants were prioritized based on the correlation of their corresponding human phenotype ontology terms with the ultrasound findings. Analyses were carried out to determine the diagnostic efficiency of pES and its correlation to the organ systems involved. The largest clinical category of fetuses referred for pES was those manifesting multisystem anomalies (104/244, 42.6%). pES provided a definitive diagnosis explaining the fetal anomalies in 47.1% (115/244) of the cases, with the identification of 122 pathogenic or likely pathogenic variants completely fitting with the phenotype. Variants of uncertain significance associated with the fetal phenotypes were detected in 84 fetuses (34%), while 18.44% (45/244) had negative results. Positive consanguinity is associated with a high diagnostic yield of ES. The novel variants and new fetal manifestations, described in our cohort, further expand the mutational and phenotypic spectrum of a wide variety of genetic disorders presenting with congenital malformations.