Molecular genetic diagnostics of Tay-Sachs disease with late clinical manifestation

Abstract

Rare clinical case of Tay-Sachs disease (TSD) with late clinical manifestation in a 33-year-old female of mixed ethnicity (Russian, Ukrainian, Mordovian, Udmurt) with symptoms of spinal amyotrophy and spinocerebellar ataxia is presented. Targeted NGS of coding regions of 300 genes clinically significant for the development of hereditary neuromuscular diseases, including gene HEXA, was carried out. Two pathogenic variants in the HEXA gene have been identified - NM_000520.6(HEXA): c.2T>C (p.Met1Thr) and c.805G>A (p.Gly269Ser). Both variants were validated by Sanger sequencing. It is well known that Gly269Ser mutation associated with the adult onset of symptoms. The phenotypes of patients with late manifestation of TSD differ significantly from infant and juvenile forms, are less known to clinicians and are worse diagnosed. The authors hope that the description of this case will complement the missing information and help in the diagnosis of TSD with late clinical manifestation.