Background and AimsKIF1A-related disorders (KRD) were first described in 2011 and the phenotypic spectrum has subsequently expanded to encompass a range of central and peripheral nervous system involvement. Here we present a case series demonstrating the range of clinical, neurophysiological and radiological features which may occur in childhood-onset KRD. MethodsWe report on all the children and young people seen at a single large tertiary centre. Data was collected through a retrospective case-notes review. Results12 individuals from 10 families were identified. Eight different mutations were present, including four novel mutations. Two patients displayed a very severe phenotype including congenital contractures, severe spasticity and/or dystonia, dysautonomia, severe sensorimotor polyneuropathy and optic atrophy, significant white matter changes on brain MRI, respiratory insufficiency, and complete lack of neurodevelopmental progress. The remaining 10 patients represented a spectrum of severity with common features including a movement disorder with spasticity and/or dystonia, subtle features of dysautonomia, sensory axonal neuropathy, varying degrees of optic atrophy and of learning and/or behavioural difficulties, and subtle or absent -but sometimes progressive -changes in white matter on MRI. Epilepsy was common among the more severely-affected children. InterpretationThis case series demonstrates that KRD comprise a range of neurological disorders, with both the milder and the more severe forms combining central and peripheral (including autonomic) nervous system deficits.

CLIPPERS (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids) is a recently described, rare neuroinflammatory disorder diagnosed by clinical symptoms involving the brain stem with a distinct pattern on neuroimaging and a perivascular T-lymphocyte infiltrate on brain biopsy. It is a condition usually described in adults in the fourth to fifth decade. We report a case of 13-year-old Indian boy who presented with recurrent episodes of ataxia and diplopia with onset at 7 years of age. He was investigated extensively to rule out infective, neoplastic, autoimmune, and demyelinating conditions over a span of 6 years. The diagnosis of CLIPPERS was entertained on the basis of clinico-radio-pathological correlation. Treatment with steroids and steroid-sparing agents, particularly methotrexate, seems to provide a promising outcome. With very few cases in literature so far, reporting of a larger case series with pediatric onset may expand it to CLIPPERS spectrum disorder.

c l i n i c a l e p i d e m i o l o g y a n d g l o b a l h e a l t h 4

In this case report, we described a 15-year-old boy who presented with intermittent episodes of ataxia and diplopia since 6.5 years of age. Extensive workup done over several years was negative. Brain biopsy showed a neuroinflammatory disorder, and hence, differential diagnosis of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids, central nervous system (CNS) lymphoma, and small vessel CNS vasculitis were considered. A final diagnosis of familial hemophagocytic lymphohistiocytosis was made when the patient developed episodes of prolonged fever with pancytopenia much later in the course of illness and genetic workup revealed pathogenic mutations in the PRF1 gene.

Aim: To investigate the rate of successful withdrawal of antiseizure medication (ASM) after starting the ketogenic diet in children and identify predictive factors.