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PubMed2025

A microcosting and cost consequence analysis from a randomized controlled trial comparing genome sequencing with exome sequencing for genetic diagnosis.

PURPOSE: Diagnosing rare diseases is costly. The objectives were to microcost exome (ES) and genome sequencing (GS) trios and estimate the incremental costs of GS per additional diagnosis from an institutional payer perspective. METHODS: Trios (proband plus biological parents) that are referred for sequencing were randomly assigned to ES or GS. Laboratory workflow and sequencing were microcosted. Total and category cost per trio were estimated probabilistically. Effectiveness was expressed as diagnostic yield (rates of diagnostic or partially diagnostic variants detected). Incremental costs and effectiveness were calculated. RESULTS: The mean total cost per trio was CAD 2888.79 (95% CI 2567.72, 3492.72) for ES (n = 329) and 4364.02 (95% CI 3984.94, 5013.67) for GS (n = 324). Reagents accounted for 34% and 61% of total costs for ES and GS, respectively. The incremental cost of GS was 1475.23. The diagnostic yield was 35.9% for ES and 32.7% for GS with a difference of 0.032 (95% CI: -0.041, 0.104, P value .397). CONCLUSION: GS demonstrated higher costs and a similar diagnostic yield to ES but was limited by technical capabilities at the time of the study. The study provides comprehensive costs for the economic evaluation comparing alternative diagnostic pathways and impetus for further evaluating variants uniquely detectable by GS.

Humans↗

PubMed2025

A meta-analysis of diagnostic yield and clinical utility of genome and exome sequencing in pediatric rare and undiagnosed genetic diseases.

PURPOSE: To systematically evaluate the diagnostic yield and clinical utility of genome sequencing (GS) and exome sequencing (ES; genome-wide sequencing [GWS]) in pediatric patients with rare and undiagnosed genetic diseases. METHODS: We conducted a meta-analysis of studies published between 2011 and 2023. To address study heterogeneity, comparative analyses included within-cohort studies using random-effects models. RESULTS: We identified 108 studies including 24,631 probands with diverse clinical indications. The pooled diagnostic yield among within-cohort studies (N = 13) for GWS was 34.2% (95% CI: 27.6-41.5; I2: 86%) vs 18.1% (95% CI: 13.1-24.6; I2: 89%) for non-GWS, with 2.4-times odds of diagnosis (95% CI: 1.40-4.04; P < .05). The pooled diagnostic yield among within-cohort studies (N = 3) for GS was 30.6% (95% CI: 18.6-45.9; I2: 79%) vs 23.2% (95% CI: 18.5-28.7; I2: 58%) for ES, with 1.7-times the odds of diagnosis (95% CI: 0.94-2.92; P = .13). In first-line testing, the diagnostic yield tended to be higher for GS than for ES across clinical subgroups. The pooled clinical utility among patients with a positive diagnosis was 58.7% (95% CI: 47.3-69.2; I2: 81%) for GS and 54.5% (95% CI: 40.7-67.6; I2: 87%) for ES. CONCLUSION: GS appears to have a higher diagnostic yield than ES, with similar clinical utility per positive diagnosis.

Child↗

PubMed2025

Impact of laboratory-driven proactive reanalysis: Reclassification to positive in 5% of initially negative or uncertain exome sequencing cases.

PURPOSE: Reanalysis of exome sequencing (ES) data increases diagnostic utility; however, there is no consensus on when and under what circumstances reanalysis should occur. Requesting and performing ES reanalysis burdens both clinical and laboratory workflows. Maximizing the potential for reclassification is essential. Here, we describe the impact of a laboratory-driven proactive reanalysis process that triggers reanalysis when new evidence is identified. METHODS: We reviewed reanalysis outcomes of an ES cohort. Reanalysis events were categorized based on initiating factors (laboratory-driven proactive, family studies, and clinician-initiated). Laboratory-driven proactive reclassifications are prompted by systematic review of new scientific data. Outcomes were evaluated by initiating factors, reclassification types, evidence used, and time since original report. RESULTS: Overall, 23% of cases underwent at least 1 reanalysis, with 35% of reanalyses resulting in reclassification. There was a 4% increase in diagnostic yield, including 5% of initially unsolved ES receiving diagnostic reports. Diagnostic reclassifications rates were significantly higher for laboratory-driven proactive reanalyses (54%; P < .0001) than family studies (18%) and clinician-initiated reanalyses (4%). New gene-disease relationships were the most efficacious evidence source. Laboratory-driven proactive reclassifications occurred steadily over time. CONCLUSION: Laboratory-driven proactive reanalysis effectively provides more diagnostic reclassifications compared with clinician-initiated reanalysis. Laboratories should curate and integrate emerging evidence into ES reanalysis.

Humans↗

PubMed2026

T-rex: standardized analysis of germline variants in whole-exome sequencing trios.

Whole-exome sequencing (WES) enables the identification of rare germline variants contributing to pediatric diseases. Trio-based sequencing, comparing affected children with their parents, is particularly effective for rare disease genetics. However, WES data analysis requires bioinformatics expertise, varies across institutions, and is often incompatible with clinical workflows. We developed T-Rex (Trio Rare variant analysis of EXomes), a cross-platform desktop application that enables the standardized and local analysis of WES germline Trio data without the need for programming knowledge. T-Rex integrates state-of-the-art tools for alignment, dual-variant calling (GATK HaplotypeCaller + VarScan2), annotation (SNPEff/SNPSift), rare-variant filtering based on population frequencies (gnomAD), and family-based statistical testing, including the Transmission Disequilibrium Test with multiple-testing correction. Benchmarking of the dual-caller strategy on the Genome in a Bottle Ashkenazim Trio demonstrates high precision (99.2%) while maintaining robust sensitivity (91.1%). User testing (n = 13) confirmed quick learning across clinicians and researchers. Application to a cohort of n = 121 pediatric cancer Trio datasets, filtering for rare protein-coding variants (MAF ≤ 0.1% in gnomAD v4.1), validated all assessable previously reported pathogenic variants. Overall, T-Rex enables clinicians to robustly analyze WES Trio data in compliance with data protection regulations without requiring additional software licenses. As one of the first platforms for comprehensive WES Trio analysis that requires no programming expertise while providing reproducible, end-to-end workflows for clinical genomics, T-Rex facilitates collaborative research between clinics and reduces reliance on external providers.

Humans↗

PubMed2026

Genetic landscape of pediatric seizures in Southeast China: identification of a novel GLI3 frameshift variant through whole-exome sequencing.

BACKGROUND: Pediatric seizure disorders are clinically and genetically heterogeneous. Whole-exome sequencing has improved the detection of rare genetic variants in childhood epilepsy; however, data from pediatric populations in Southeast China remain limited. This study aimed to characterize the genetic landscape of pediatric seizure disorders in Southeast China and to evaluate the clinical diagnostic yield of whole-exome sequencing. MATERIALS AND METHODS: This retrospective observational study included 21 pediatric patients with seizure disorders who were recruited at the Fifth Hospital of Xiamen, Fujian, China, between January 2021 and June 2024. Clinical data were extracted from medical records. Whole-exome sequencing was performed on DNA extracted from peripheral blood. Sequence variants were annotated, filtered, and classified according to the guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Copy-number variants were evaluated using exome-based algorithms. Descriptive statistics were used because of the limited sample size. RESULTS: WES identified three clinically relevant, likely pathogenic findings in 3 of 21 patients, corresponding to a provisional diagnostic yield of 14.3%. The remaining 62 of 65 variants were of uncertain significance (VUS). The three retained variants included a GLI3 frameshift variant (exon 2: c.90_91insCAGATGTGAGC; p.Glu31Glnfs*3) and two copy-number variants (16p13.12-16p13.11 duplication and Xp22.31 deletion) with established clinical significance. Functional analysis of all 65 variants revealed that ion channel genes and neurodevelopmental genes were the most frequently affected categories. CONCLUSION: Whole-exome sequencing identified clinically relevant genetic findings in a subset of Southeast Chinese children with seizure disorders. The novel GLI3 frameshift variant may suggest an expansion of the GLI3-associated phenotypic spectrum, but further segregation, functional validation, and larger cohort studies are needed. The high proportion of variants of uncertain significance highlights the ongoing challenges of genetic interpretation in pediatric seizure disorders.

GLI3 frameshift variant↗

PubMed2025

Diagnostic Yield After Postnatal Reanalysis of Prenatal Exome Sequencing Results.

OBJECTIVE: Analysis of exome sequencing (ES) relies on correlation with phenotypic features, but fetal phenotyping is often incomplete. The additional yield of postnatal follow-up in cases with negative or inconclusive prenatal ES has not been demonstrated. Our objective was to assess the incremental diagnostic yield of ES reanalysis after initially negative prenatal ES for congenital anomalies incorporating features identified postnatally. METHODS: This was a secondary analysis of two prospective cohort studies of ES for fetal anomalies. We included cases in which initial ES utilizing the prenatal phenotype was not diagnostic. The primary outcome was incremental diagnostic yield of ES when incorporating postnatal findings. RESULTS: Eighty-seven cases with negative or inconclusive prenatal ES and postnatal follow-up available were included. Of those, 56 (64%) had new findings postnatally. There was an incremental yield of 2% in the entire cohort, and 7% in those with new postnatal findings. In two additional cases, postnatal evaluation suggested a specific genetic diagnosis that was not detectable with ES. CONCLUSION: Among pregnancies with fetal anomalies and no clear diagnosis identified by prenatal ES, postnatal follow-up is recommended. Reanalysis of ES results can result in a genetic diagnosis in 7% of cases with new findings.

Humans↗

PubMed2026

Whole-Exome Sequencing in a Consanguinity-Enriched South Indian Retinitis Pigmentosa Cohort: Diagnostic Yield and Molecular Spectrum.

PURPOSE: To determine the molecular diagnostic yield, variant spectrum, inheritance architecture, and influence of consanguinity on whole-exome sequencing outcomes in a South Indian retinitis pigmentosa (RP) cohort. DESIGN: Prospective, registry-based cohort study. SUBJECTS: A total of 113 affected participants were enrolled through the Aravind Registry for Inherited Diseases of the Eye, including 109 unrelated probands and 4 affected relatives from already represented families. Primary analyses were restricted to the 109 unrelated probands. METHODS: Whole-exome sequencing was performed using a clinical exome workflow. Variants were interpreted using American College of Medical Genetics and Genomics/Association for Molecular Pathology criteria and cases were categorized as solved, possibly solved, inconclusive, or unsolved using prespecified inheritance-aware rules. MAIN OUTCOME MEASURES: Molecular diagnostic yield, distribution of implicated genes and variant classes, inheritance architecture, and diagnostic yield stratified by consanguinity status. RESULTS: Among the 109 unrelated probands, mean age at testing was 39.3 ± 14.1 years and 58.7% were male. Whole-exome sequencing identified 186 distinct rare variants across 92 inherited retinal disease genes, including 26 pathogenic and 33 likely pathogenic variants. A molecular diagnosis was established in 50 of 109 probands (45.9%), including 42 solved and 8 possibly solved cases; 45 (41.3%) were inconclusive and 14 (12.8%) remained unsolved, including 4 (3.7%) in whom no candidate variant was identified. EYS, USH2A, and ADGRV1 were the most frequently implicated genes. Autosomal recessive (AR) disease predominated (44/50, 88.0%). Consanguineous AR cases were exclusively homozygous (17/17); notably, 68.0% of nonconsanguineous AR cases were also homozygous (P = 0.013). Diagnostic yield was higher in consanguineous probands (51.4% vs. 41.7%), without reaching significance. Recurrent alleles included an established South Asian founder variant (MFSD8 c.1361T>C) and candidate founder alleles in EYS (c.4321C>T) and ADGRV1 (c.14329C>T). CONCLUSIONS: Whole-exome sequencing established a molecular diagnosis in nearly half of this South Indian RP cohort and revealed a predominantly recessive, homozygosity-enriched architecture shaped by consanguinity. These findings define a region-specific variant landscape to support clinical interpretation, genetic counseling, and future trial enrollment in this underrepresented population. FINANCIAL DISCLOSURES: The authors have no proprietary or commercial interest in any materials discussed in this article.

Consanguinity↗

PubMed2024

Genomic landscape of hepatocellular carcinoma in Egyptian patients by whole exome sequencing.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Chronic hepatitis and liver cirrhosis lead to accumulation of genetic alterations driving HCC pathogenesis. This study is designed to explore genomic landscape of HCC in Egyptian patients by whole exome sequencing. METHODS: Whole exome sequencing using Ion Torrent was done on 13 HCC patients, who underwent surgical intervention (7 patients underwent living donor liver transplantation (LDLT) and 6 patients had surgical resection}. RESULTS: Mutational signature was mostly S1, S5, S6, and S12 in HCC. Analysis of highly mutated genes in both HCC and Non-HCC revealed the presence of highly mutated genes in HCC (AHNAK2, MUC6, MUC16, TTN, ZNF17, FLG, MUC12, OBSCN, PDE4DIP, MUC5b, and HYDIN). Among the 26 significantly mutated HCC genes-identified across 10 genome sequencing studies-in addition to TCGA, APOB and RP1L1 showed the highest number of mutations in both HCC and Non-HCC tissues. Tier 1, Tier 2 variants in TCGA SMGs in HCC and Non-HCC (TP53, PIK3CA, CDKN2A, and BAP1). Cancer Genome Landscape analysis revealed Tier 1 and Tier 2 variants in HCC (MSH2) and in Non-HCC (KMT2D and ATM). For KEGG analysis, the significantly annotated clusters in HCC were Notch signaling, Wnt signaling, PI3K-AKT pathway, Hippo signaling, Apelin signaling, Hedgehog (Hh) signaling, and MAPK signaling, in addition to ECM-receptor interaction, focal adhesion, and calcium signaling. Tier 1 and Tier 2 variants KIT, KMT2D, NOTCH1, KMT2C, PIK3CA, KIT, SMARCA4, ATM, PTEN, MSH2, and PTCH1 were low frequency variants in both HCC and Non-HCC. CONCLUSION: Our results are in accordance with previous studies in HCC regarding highly mutated genes, TCGA and specifically enriched pathways in HCC. Analysis for clinical interpretation of variants revealed the presence of Tier 1 and Tier 2 variants that represent potential clinically actionable targets. The use of sequencing techniques to detect structural variants and novel techniques as single cell sequencing together with multiomics transcriptomics, metagenomics will integrate the molecular pathogenesis of HCC in Egyptian patients.

Humans↗

PubMed2022

Feasibility of a novel non-invasive swab technique for serial whole-exome sequencing of cervical tumors during chemoradiation therapy.

BACKGROUND: Clinically relevant genetic predictors of radiation response for cervical cancer are understudied due to the morbidity of repeat invasive biopsies required to obtain genetic material. Thus, we aimed to demonstrate the feasibility of a novel noninvasive cervical swab technique to (1) collect tumor DNA with adequate throughput to (2) perform whole-exome sequencing (WES) at serial time points over the course of chemoradiation therapy (CRT). METHODS: Cervical cancer tumor samples from patients undergoing chemoradiation were collected at baseline, at week 1, week 3, and at the completion of CRT (week 5) using a noninvasive swab-based biopsy technique. Swab samples were analyzed with whole-exome sequencing (WES) with mutation calling using a custom pipeline optimized for shallow whole-exome sequencing with low tumor purity (TP). Tumor mutation changes over the course of treatment were profiled. RESULTS: 216 samples were collected and successfully sequenced for 70 patients (94% of total number of tumor samples collected). A total of 33 patients had a complete set of samples at all four time points. The mean mapping rate was 98% for all samples, and the mean target coverage was 180. Estimated TP was greater than 5% for all samples. Overall mutation frequency decreased during CRT but mapping rate and mean target coverage remained at >98% and >180 reads at week 5. CONCLUSION: This study demonstrates the feasibility and application of a noninvasive swab-based technique for WES analysis which may be applied to investigate dynamic tumor mutational changes during treatment to identify novel genes which confer radiation resistance.

Exome↗

PubMed2024

Exome sequencing reveals neurodevelopmental genes in simplex consanguineous Iranian families with syndromic autism.

BACKGROUND AND OBJECTIVE: Autosomal recessive genetic disorders pose significant health challenges in regions where consanguineous marriages are prevalent. The utilization of exome sequencing as a frequently employed methodology has enabled a clear delineation of diagnostic efficacy and mode of inheritance within multiplex consanguineous families. However, these aspects remain less elucidated within simplex families. METHODS: In this study involving 12 unrelated simplex Iranian families presenting syndromic autism, we conducted singleton exome sequencing. The identified genetic variants were validated using Sanger sequencing, and for the missense variants in FOXG1 and DMD, 3D protein structure modeling was carried out to substantiate their pathogenicity. To examine the expression patterns of the candidate genes in the fetal brain, adult brain, and muscle, RT-qPCR was employed. RESULTS: In four families, we detected an autosomal dominant gene (FOXG1), an autosomal recessive gene (CHKB), and two X-linked autism genes (IQSEC2 and DMD), indicating diverse inheritance patterns. In the remaining eight families, we were unable to identify any disease-associated genes. As a result, our variant detection rate stood at 33.3% (4/12), surpassing rates reported in similar studies of smaller cohorts. Among the four newly identified coding variants, three are de novo (heterozygous variant p.Trp546Ter in IQSEC2, heterozygous variant p.Ala188Glu in FOXG1, and hemizygous variant p.Leu211Met in DMD), while the homozygous variant p.Glu128Ter in CHKB was inherited from both healthy heterozygous parents. 3D protein structure modeling was carried out for the missense variants in FOXG1 and DMD, which predicted steric hindrance and spatial inhibition, respectively, supporting the pathogenicity of these human mutants. Additionally, the nonsense variant in CHKB is anticipated to influence its dimerization - crucial for choline kinase function - and the nonsense variant in IQSEC2 is predicted to eliminate three functional domains. Consequently, these distinct variants found in four unrelated individuals with autism are likely indicative of loss-of-function mutations. CONCLUSIONS: In our two syndromic autism families, we discovered variants in two muscular dystrophy genes, DMD and CHKB. Given that DMD and CHKB are recognized for their participation in the non-cognitive manifestations of muscular dystrophy, it indicates that some genes transcend the boundary of apparently unrelated clinical categories, thereby establishing a novel connection between ASD and muscular dystrophy. Our findings also shed light on the complex inheritance patterns observed in Iranian consanguineous simplex families and emphasize the connection between autism spectrum disorder and muscular dystrophy. This underscores a likely genetic convergence between neurodevelopmental and neuromuscular disorders.

Humans↗

PubMed2025

Whole-exome sequencing uncovers the genetic basis of hereditary concomitant exotropia in ten Chinese pedigrees.

PURPOSE: To explore possible pathogenic genes for concomitant exotropia using whole-exome sequencing. METHODS: In this study, 47 individuals from 10 concomitant exotropia (including intermittent exotropia and constant exotropia) pedigrees were enrolled. Whole-exome sequencing was used to screen mutational profiles in 25 affected individuals and 10 unaffected individuals. Sanger sequencing and in silico analysis were performed for all participants. Two target genes were used to capture the sequences of 220 sporadic samples. RESULTS: All 10 concomitant exotropia pedigrees presented autosomal dominant inheritance with childhood onset (3.35 ± 1.51 years old). Eleven different missense variants were identified among seven potential pathogenic genes (COL4A2, SYNE1, LOXHD1, AUTS2, GTDC2, HERC2 and CDH3) that cosegregated with pedigree members. All variants were predicted to be deleterious and had low frequencies in the general population. Distinct variants of COL4A2 were present in three pedigrees, and distinct variants of SYNE1 were present in two pedigrees. Fifteen variants in AUTS2 and four variants in GTDC2 were identified in 220 patients with sporadic concomitant exotropia using a target-capture sequencing approach. CONCLUSION: This is the first study to explore the genetic mechanism of concomitant exotropia and identify seven associated genes (COL4A2, SYNE1, LOXHD1, AUTS2, GTDC2, HERC2 and CDH3) that may be candidate genes causing concomitant exotropia. More samples and in-depth studies are needed to verify these findings.

Adult↗

PubMed2025

Trio exome sequencing identifies de novo variants in novel candidate genes in 19.62% of CAKUT families.

PURPOSE: Congenital anomalies of the kidney and urinary tract (CAKUT) encompass heterogenous malformations arising from defective nephrogenesis. To date, approximately 50 monogenic genes are known to cause CAKUT if mutated. Recent studies show the impact of de novo variants in genetic disease etiology. Trio exome sequencing identifies de novo variants in novel candidate genes in 19.62% of CAKUT families. METHODS: We performed trio-based exome sequencing in 209 families with CAKUT to detect novel candidate disease genes. RESULTS: Trio analysis yielded in the identification of CAKUT candidate genes in 96 of 209 trio families (45.93%). In 41 of 209 cases, we detected strong de novo variants in 45 potential novel CAKUT candidate genes (19.62%). We developed a prioritization approach that highlights a truncating de novo variant in SOX13 (HGNC:11192) as a promising cause for CAKUT. In addition, further allele carriers for the candidate gene CHD1L (HGNC:1916) were identified, thus supporting the role of CHD1L in the pathogenesis of CAKUT. CONCLUSION: We conclude that de novo variants in potential novel CAKUT candidate genes contribute to the disease etiology and present SOX13 as a potential novel cause for CAKUT.

Humans↗

PubMed2026

Whole-exome Sequencing Identifies Novel Candidate PCNT Variants in a Child With Overlapping MOPD II Features: A Case Report.

A 7-year-old Chinese boy presented with severe postnatal growth failure (height <3rd percentile at age 7 years), global developmental delay, moderate intellectual disability, and characteristic dysmorphic features including hypertelorism, short palpebral fissures, low-set ears, and a broad nasal bridge. A single electrocardiogram demonstrated a borderline corrected QT interval (QTc = 450 ms). No arrhythmias, QT-prolonging medications, electrolyte abnormalities, or relevant family cardiac history were identified. This finding warrants longitudinal cardiology follow-up and should not be interpreted as definitive Long QT syndrome. Whole-exome sequencing identified two novel missense variants in the PCNT gene (NM_006031.5): c.5675A>G (p.Glu1892Gly) in exon 28 and c.9734G>T (p.Arg3245Ile) in exon 45. Both variants were absent from gnomAD, ExAC, the 1000 Genomes Project database, and Chinese population databases, fulfilling ACMG criterion PM2. Although classified as variants of uncertain significance (VUS) because of limited functional evidence and conflicting in silico predictions, the variants occur in a gene associated with primordial dwarfism and are accompanied by partial phenotypic overlap with Microcephalic Osteodysplastic Primordial Dwarfism Type II (MOPD II). However, parental segregation analysis was unavailable; therefore, the variant phase could not be confirmed, and a recessive disease mechanism could not be established. These findings support the presence of candidate PCNT variants in an atypical primordial dwarfism phenotype and illustrate the utility of whole-exome sequencing for generating testable molecular hypotheses in genetically heterogeneous growth disorders. A definitive molecular diagnosis cannot be established at present, and the isolated borderline QTc finding requires further clinical evaluation.

Humans↗

PubMed2025

Exome sequencing revealed a novel homozygous variant in TRMT61 A in a multiplex family with atypical Cornelia de Lange Syndrome from Rwanda.

BACKGROUND: In 30% of patients who exhibit the clinical profile of Cornelia de Lange Syndrome (CdLS), the genetic cause remains undetermined. This proportion tends to be higher in low-resource settings including Africa. We performed a molecular characterization of CdLS in a multiplex Rwandan family. METHODS: After a clinical evaluation of two affected siblings, DNA isolated from peripheral whole blood of the affected patients and their parents underwent Exome Sequencing (ES). Sanger sequencing validated the variant segregating with CdLS. In silico predictive tools, protein modelling, and cell-based experiments using HEK293T cells were used to investigate the pathogenicity of the variant found. RESULTS: We identified a family with two parents and their two offspring (male and female), who were referred for hearing impairment. The 17-year-old female presented bilateral profound hearing impairment with moderate hypertelorism, progressive visual impairment, and secondary amenorrhea. The 14-year-old male displayed intellectual disability and a bilateral profound hearing impairment with no noticeable facial dysmorphism. Following exome sequencing (ES) of DNA samples obtained from the four family members, we found that the siblings harbored a novel likely pathogenic homozygous missense variant in the TRMT61 A gene [NM_152307.3:c.665C > T p.(Ala222Val)] inherited from both heterozygous parents. In silico analysis suggested that the variant substitutes a highly conserved amino acid, and 2-D structure modelling revealed a significant decrease in the stability of the protein. Cell-based experiment in HEK293T showed that the variant significantly affected the TRMT61 A protein localization which is thought to impact the mitochondrial and cytosolic functions. CONCLUSION: We reported a novel biallelic variant in TRMT61 A, [NM_152307.3:c.665C > T p.(Ala222Val)], which is associated with autosomal recessive atypical CdLS in a multiplex Rwandan family, the first report from Africa, and the second globally. The study emphasizes the need to expand the availability of ES for molecular characterization of rare diseases for the understudied genetically diverse population of Africa.

Humans↗

PubMed2025

Exome sequencing identifies a homozygous splice site variant in RP1 as the underlying cause of autosomal recessive retinitis pigmentosa in a Pakistani family.

BACKGROUND: Mutations in RP1 gene are the third leading cause of inherited retinal dystrophies (IRDs) in Pakistani families. PATIENTS: A two-generation consanguineous Pakistani family underwent both clinical and genetic analyses. Clinical examinations included visual acuity test, visual field, fundoscopy, and ocular coherence tomography (OCT). Whole exome sequencing (WES) was performed on the proband's DNA, and Sanger sequencing was performed to validate the WES findings. Splicing prediction tools such as Human Splicing Finder (HSF), NNSplice predictor, SpliceAI, MaxENTScan, and SpliceRover were used. RESULTS: A nuclear family of seven children, comprising five affected individuals (four males and one female) and two healthy siblings, was recruited from northwestern Pakistan. The proband was a 49-years old male who was presented with complaints of decreased visual acuity and night blindness since early childhood. Upon clinical evaluation, the proband appeared to have severely reduced visual acuity of hand movement (HM), bilateral visual field constriction, a waxy pale disc with vascular attenuation, pigmentary bone spicules at the periphery associated with chorioretinal degeneration, diffuse macular atrophy, and horizontal nystagmus in both of his eyes. Exome sequencing (ES) in the proband identified a homozygous splice site variant (NM_006269.2: c.615 + 1G > A) in RP1 gene. In-silico analysis, genotype-phenotype co-segregation study, and literature survey strongly supported the causality of the detected variant. CONCLUSIONS: We report a previously known pathogenic splice site variant of RP1 as the underlying cause of early-onset autosomal recessive retinitis pigmentosa (arRP) in a Pakistani family. We contemplate that the detected allele might constitute a mutational hotspot in RP1.

Humans↗

PubMed2025

Monogenic disorders associated with motor speech phenotypes in children and adolescents undergoing clinical exome sequencing.

PURPOSE: Prior studies investigating the genetic architecture of pediatric motor speech disorders (MSDs) have been limited by small sample sizes and an exclusive focus on apraxia. We aimed to identify pathogenic genomic variants associated with MSDs in a large pediatric population referred for exome sequencing (ES). METHODS: We identified pediatric patients with MSDs who had clinical ES between 2012 and 2022. The rate of pathogenic/likely pathogenic (P/LP) findings considered causative of the MSD phenotype was determined and delineated by sex and neurodevelopmental comorbidity. Gene-based burden testing compared the rate of P/LP variants in each gene in MSD cases with a comparison clinical ES cohort. RESULTS: Positive diagnostic results were detected in 527 of 2004 (26.3%) patients with MSDs, with higher diagnostic rates in females and individuals with neurodevelopmental comorbidities. P/LP sequence variants were detected in 262 genes. Gene-based case-referent burden analysis revealed that 30 genes were nominally associated with MSDs, 2 of which (SETBP1 and ADCY5) survived exome-wide correction. CONCLUSION: Over 25% of patients with MSDs were found to harbor P/LP variants in 262 genes, many of which have not previously been associated with MSDs. Potential clinical implications include early implementation of intensive speech therapy for children diagnosed with monogenic causes of MSDs.

Humans↗

PubMed2025

Diagnostic and clinical utility of exome sequencing and chromosomal microarray in children with GDD/iD: a meta-analysis.

BACKGROUND: Global developmental delay/intellectual disability (GDD/ID) is among the most common neurodevelopmental disorders, with up to half of cases are attributed to genetic factors. Chromosome microarray (CMA) has traditionally been the primary genetic test for idiopathic GDD/ID. However, whole exome sequencing (WES) and whole genome sequencing (WGS) have recently emerged, substantially increasing diagnostic yields in these populations. METHODS: We conducted a comprehensive literature search of PubMed, Scopus, EMBASE, and the Cochrane Library from inception to April 29, 2025. Studies reporting the diagnostic utility of these tests in children with GDD/ID were included and analyzed. RESULTS: A total of 102 studies, comprising 55,752 children, were reviewed. The pooled diagnostic yield of WES was 0.37 (95% CI: 0.33-0.41; I2 = 93%), significantly higher than that of CMA at 0.19 (95% CI: 0.16-0.21; I2 = 95%). Subgroup analyses showed that WES yielded significantly higher diagnostic rates than CMA in both same-sample comparisons (OR = 2.27, 95% CI: 1.08-4.78) and different-sample comparisons (OR = 1.65, 95% CI: 1.15-2.37). Only one study evaluated WGS, reporting a diagnostic yield of 0.27. Meta-regression revealed a significant association between CMA diagnostic yield and the proportion of male participants (p < 0.01), but not with WES. No significant difference in diagnostic utility was observed between isolated GDD/ID and GDD/ID with comorbidities. CONCLUSION: In children with unexplained GDD/ID, WES demonstrates superior diagnostic and clinical utility compared to CMA. Incorporating WES as a first-line investigation in the diagnostic evaluation of GDD/ID may be warranted.

Humans↗

PubMed2026

Whole-Exome Sequencing Identified a Novel Mutation in an Iranian Patient with Epidermolysis Bullosa.

BACKGROUND: Epidermolysis bullosa (EB) is a rare, genetically heterogeneous disorder characterized by skin fragility. EB is categorized into four types: simplex, junctional, dystrophic, and Kindler syndromes. The condition is caused by mutations in several genes that are important for skin integrity and dermal-epidermal adhesion. In the present study, we recruited a patient with EB from an Iranian pedigree for genetic evaluation. METHODS: Whole-exome sequencing (WES) and bioinformatics analysis were performed using genomic DNA from the patient with EB. The potential variant was confirmed by Sanger sequencing. RESULTS: We identified a novel likely pathogenic variant in exon 3 of the COL17A1 gene: c.82dup (p.Thr28Asnfs15). The patient's parents were heterozygous carriers of this mutation. In silico structural prediction suggested that this variant could cause premature termination of COL17A1. This variant is associated with intermediate junctional EB-4 (JEB4). CONCLUSION: This study highlights that WES enhances our understanding of genetic diagnosis, and it contributes to the expanded mutational spectrum of the COL17A1 gene associated with JEB.

Humans↗