PURPOSE
TCF7L2 (OMIM:602228; HGNC:11641) is a transcription factor and critical effector of the Wnt/β-Catenin pathway. In 2021, 11 pediatric patients with mono-allelic predicted loss-of-function (pLOF) TCF7L2 variants and syndromic features were observed. Characterization of patients with pLOF TCF7L2 variants and neurodevelopmental features - herein referred to as TCF7L2-related neurodevelopmental disorder (TRND) - is urgently needed.
METHODS
We leveraged multiple methods (GeneMatcher, DECIPHER, literature review, public/private repositories) to identify an international cohort of 76 patients with pLOF TCF7L2 variants and neurodevelopmental features and phenotypically characterized them. We also retrospectively searched for an independent cohort of adults with pLOF TCF7L2 variants (n = 11) from 60,000+ PennMedicine BioBank (PMBB) patients.
RESULTS
Among 76 patients with pLOF TCF7L2 variants, speech delay (95.3%), craniofacial dysmorphisms (73.3%), ophthalmologic conditions (65.5%), autism (62.1%), and orthopedic abnormalities (52.6%) were most commonly observed. Phenotypic differences did not cluster by variant type or genomic locus. Among PMBB patients, an association of nominal significance with type 2 diabetes with renal manifestations (OR = 5.8; p-value = 0.03) was detected, warranting further investigation.
CONCLUSIONS
This represents the most comprehensive characterization to date of TRND, a novel neurodevelopmental disorder, defining its genotypic and phenotypic spectrum. We opened a Simons Searchlight natural history study (https://www.simonssearchlight.org/research/what-we-study/tcf7l2/) to enhance understanding of this condition.
Sally Nijim, Mimi Kim, Melissa Denish et al.· Genetics in Medicine· 1 citation
Congenital eye malformations represent a clinically and genetically heterogeneous group of disorders. Despite advances in genetic testing, fewer than half of affected patients receive a definitive molecular diagnosis. However, obtaining a molecular diagnosis is crucial for these patients and their families. Whole genome sequencing (WGS) is now standard practice in the genetic investigation of patients, but its contribution has not been extensively evaluated in patients with ocular malformations. In this work, we performed short-read WGS in a cohort of 100 families presenting with eye developmental disorders, including microphthalmia-anophthalmia spectrum (M/A), coloboma, anterior segment dysgenesis, congenital cataracts and/or foveal hypoplasia. Prior to WGS, 47 individuals had undergone targeted next-generation sequencing (NGS) of genes panels related to ocular development, 11 had chromosomal microarray analysis (CGH-array) and 20 had a combination of both. None had received a definitive genetic diagnosis. WGS identified a (likely) pathogenic variant in eighteen patients. In addition, candidate variants of uncertain significance were detected in nine patients. Notably, fourteen of these variants would have been missed by conventional genes panels or CGH-array, underscoring the broader diagnostic scope of WGS. Our findings demonstrate that short-read WGS significantly improves diagnostic yield in patients with congenital eye malformations, including those previously undiagnosed despite NGS panel testing. These results support the integration of WGS in the genetic evaluation of ocular developmental disorders.
Bertrand Chesneau, Timotéo Cousteix, Abdelhakim Bouazzaoui et al.· European Journal of Human Ge...· 1 citation· ⚡1