Novel splice site mutations in a patient with late atypical onset Tay-Sachs disease: importance of combined NGS and biochemical analysis.

Tay-Sachs disease (TSD) is a rare genetic disorder with diverse clinical manifestations, often leading to underdiagnosis due to symptom similarities with other neurological conditions. In this study, we aimed to identify the genetic mutations underlying late-onset TSD in a 27-year-old patient with progressive neurological symptoms. Whole-exome sequencing revealed two gene mutations associated with TSD: a previously known variant, c.805G > A (p.Gly269Ser), and a novel splice-site mutation, c.346 + 2dupT. Through clinical assessments, genetic analysis, and functional investigations-including RNA sequencing and enzymatic activity assays-we confirmed the pathogenicity of the novel mutation. Our findings highlight the efficacy of advanced genomic technologies in diagnosing intricate genetic disorders and emphasize the significance of functional validation to confirm the effects of mutations. Identifying compound heterozygous mutations in the gene also provides insight into Mendelian inheritance patterns. This case highlights the diagnostic challenges posed by overlapping clinical phenotypes and emphasizes the need for increased genetic awareness among clinicians. Accurate diagnosis of TSD has significant implications for patients and their families, allowing for informed genetic counseling and guiding clinical management decisions. While current treatment options are limited, timely and accurate diagnosis holds promise for future research and therapeutic interventions. This study highlights the value of a multidisciplinary approach in exploring the molecular basis of complex genetic diseases and informing clinical decisions.