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.

Exceptionally high creatine kinase levels in risperidone-induced neuroleptic malignant syndrome: A case report.

Neuroleptic malignant syndrome is a rare, fatal antipsychotic-induced idiosyncratic reaction characterised by hyperthermia, altered consciousness, autonomic instability and rigidity with elevated creatine kinase levels and leukocytosis. Neuroleptic malignant syndrome and antipsychotics are significant causes for elevated creatine kinase among the extensive list of differential diagnoses. Risperidone is an atypical antipsychotic drug with anti-serotonergic and anti-dopaminergic properties which has a wide range of side effects, including neuroleptic malignant syndrome. Though the rise in creatine kinase in neuroleptic malignant syndrome is commonly around 2000 to 15,000 IU/L due to myonecrosis, ischaemia and heat production, normal creatine kinase levels in neuroleptic malignant syndrome were also reported. Up to now, only two cases have been reported with creatine kinase levels of more than 50,000 IU/L in neuroleptic malignant syndrome, but neither of them was risperidone-induced. We report the first case of an exceptional rise in creatine kinase levels more than 250-fold in a 16-year-old girl following low-dose risperidone-induced neuroleptic malignant syndrome.