Introduction: The gene TBC1D24 is involved in regulation of synaptic vesicle trafficking and in brain and somatic development. TBC1D24-related disorders comprise a continuum of features and includes seizures, developmental and epileptic encephalopathy, skeletal and dental abnormalities, myoclonus and hearing loss. They have a slowly progressive course with a refractory myoclonus that can go on for hours resembling focal status epilepticus Methodology: We describe four genetically confirmed cases with TBC1D24 gene related disorders. Results: 3 cases had a developmental and epileptic encephalopathy (DEE) phenotype while one had a progressive myoclonus epilepsy (PME) phenotype. 2 cases were males and 2 had a history of parental consanguinity. All patients presented with seizures with onset between 1.5 to 5 months of age. All had global developmental delay with tone abnormalities. Microcephaly was noted in 3 children while dysmorphism was absent in our cohort. Neuroimaging showed cerebral atrophy in all 3 cases with DEE phenotype with Case 2 having cerebellar atrophy too. Case 2 with PME phenotype had cerebellar atrophy. EEG was normal in all except one DEE patient where multifocal epileptiform discharges were noted. Three out of four cases seizures showed a good response to oral Triclofos after having received a trial of multiple anti-seizure medications. (Table attached) Conclusion: TBC1D24 gene related disorders have resistant epilepsy and although the EEGs do not show a high burden of epileptic discharges, these children can have status epilepticus. Incessantly continuing myoclonus may often be labelled as status epilepticus and overtreated. Multifocal myoclonus responds well to Triclofos.

Ashwin Sardesai
Jawaharlal Nehru Medical College
India

Mahesh Kamate
Jawaharlal Nehru Medical College
India

Bhavana Koppad
Jawaharlal Nehru Medical College
India