Novel mutation of EXOSC3 presenting as hereditary spastic paraplegia plus syndrome

Abstract

RNA processing protein 40 (RRP40) is an exosome complex involved in processing RNA, of which EXOSC3 forms a non-catalytic subunit. Homozygous mutation in EXOSC3 causes Pontocerebellar hypoplasia-1 (PCH-1), characterised by postnatal psychomotor retardation with spinal motor neuron degeneration. Imaging in PCH-1 shows severe cerebellar and variable pontine atrophy. Here we report an adolescent male with EXOSC3 mutation who presented with spastic paraparesis and nystagmus since childhood with severe vermian atrophy and normal pons suggestive phenotypically Hereditary spastic paraplegia plus syndrome (HSP-Plus).