Clinical Presentation and Genetic Heterogeneity Including Two Novel Variants in Sri Lankan Patients With Infantile Sandhoff Disease

Infantile Sandhoff Disease (iSD) is a subtype of GM2 gangliosidosis, which is never been reported in Sri Lanka. Data of eight children, who were diagnosed with iSD during the period of 2017 to 2021, were analyzed retrospectively. The aim of this study was to analyze genotypic and phenotypic variations of native iSDs. Café-au-lait spots, mitral regurgitation and atrial septal defect were found in our patients but never reported in the literature. We found c.1417 + 5G>A and c.1303_1304insCT p.(Arg435Thrfs*10) novel variants of HEXB gene among the nine different gene mutations that were identified. The commonest HEXB gene variant identified in India was c.850 C4T (p.R284X) but was not noticed among Sri Lankan patients. In contrast to other studies, all our patients died within the age of two years. This is the first Sri Lankan study that expands the clinical and molecular basis of iSD with its novel findings.