SPTAN1 related epileptic encephalopathy- a case study

Objective To share a case study of a child diagnosed with SPTAN1 gene mutation and highlight peculiar features of this evolving distinct clinical syndrome. Methods: Review of case notes and literature. Results: Our patient delivered at term in good condition following a normal pregnancy. She had poor tone and choking episodes from early on. She presented at 3 months of age with infantile spasms and was treated with steroids and vigabatrin. After an initial response to treatment, she started having spasms refractory to treatment (Multiple AED’s, ketogenic diet). Examination revealed marked hypotonia and paucity of spontaneous movements. At 3 years, she showed significant global developmental delay, microcephaly, bilateral sensorineural deafness, nystagmus and showing signs consistent with evolving spastic quadriplegia with dystonic spasms. An EEG revealed classical hypsarrhythmia with an earlier diagnosis of West syndrome. MRI brain showed cerebellar atrophy and subsequently she was found to have SPTAN1 gene mutation on WGS.

Conclusion Mutations in SPTAN1 is a rare known cause for early onset epileptic encephalopathy. It presents with a distinct clinical syndrome. Features include epileptic encephalopathy with hypsarrhythmia, acquired microcephaly, spastic quadriplegia and severe intellectual disability. Brainstem and cerebellar atrophy and cerebral hypomyelination are specific hallmarks of this condition 1. Our patient presented with typical features of this known gene mutation, thus reinforcing the idea that SPTAN1 encephalopathy is a distinct clinical syndrome. Early recognition is important for proper diagnostic work- up. References: 1. Tohyama J, et al. SPTAN1 encephalopathy: distinct phenotypes and genotypes. J Hum Genet 60, 167-173 (2015).