Genomic newborn screening for actionable, sight-threatening eye diseases.
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Biomedical subjects
Publications and source records attributed to Laura Helou.
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INTRODUCTION: Autism spectrum disorder (ASD) is a neurodevelopmental condition with substantial genetic and phenotypic heterogeneity. However, populations of African ancestry remain underrepresented in genomic studies, limiting understanding of ASD genetic architecture. This study aimed to characterize rare, clinically relevant genetic variants in a Rwandan pediatric ASD cohort using trio-based whole-exome sequencing (WES). METHODS: Trio-based WES was performed in 31 Rwandan pediatric patients with ASD (aged 2-18 years) and their parents. Variants were analyzed using a trio-based workflow and classified according to American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines. RESULTS: Eleven candidate variants were identified in 9 of 31 patients, including four likely pathogenic variants and seven variants of uncertain significance. This resulted in a diagnostic yield of 12.9% (4/31), expanded to 29.0% when phenotypically concordant variants of uncertain significance were considered. Most likely pathogenic variants were identified in individuals with syndromic ASD who presented with intellectual disability, epilepsy, and global developmental delay. Likely pathogenic findings included two single nucleotide variants in GABRB3, SYNGAP1, and two copy-number variants involving the GNAS locus and chromosome 1p35.3-p35.2. CONCLUSIONS: The diagnostic yield observed in this cohort is consistent with previous trio-based WES studies of ASD. The findings support the clinical utility of WES for the genetic evaluation of ASD and underscore the need for expanded genomic studies in African populations.
Baby Detect Project, started in September 2022, aimed to create a newborn screening test using targeted next-generation sequencing for all early-onset, treatable, and serious conditions. The elaborated gene panel covers 405 genes, associated with 165 genetic conditions, and includes RB1, linked to retinoblastoma, the only oncological disease tested for. Germline RB1 mutations concern around 50% of all retinoblastoma cases and 100% of the most severe, bilateral cases. Ninety percent of them occur de novo, which delays the diagnosis by about a year with subsequent loss of vision and sometimes the eye itself. Detecting children with germline RB1 mutation at birth would greatly improve functional and anatomic outcomes, limiting invasive treatments and general anesthesias through early childhood. We discuss herein the novel approach of population screening, the rationale for newborn testing for RB1 mutations, the incidence of expected cases, the reliability of the test and its costs. The next step is to move to a nation-scale population; this initiative marks a landmark in retinoblastoma patients' care.