Ceroid lipofuscinosis type 5 (CLN5) gene mutation associated adult-onset cerebellar ataxia

Abstract

Neuronal ceroid lipofuscinosis (NCL) associated inherited ataxia are expanding heterogenous group of neurodegenerative disorders. Adult-onset neurological phenotypes represents 5% of the CLN mutations, and onset of symptoms usually occurs at the second to forth decades. We present a patient who had a relatively late onset of symptoms in association with a variant mutation in the CLN5 gene. Case report. A 52-year-old male, who presented with history of progressive unsteady gait. He denied any cognitive or behavioral disturbance. His parents are second degree cousins and he have 7 brothers and 3 sisters, none of which has similar symptoms or known to have any neurologic disease. His wife is not relative, and he has 9 healthy children. On examination, he was fully oriented, alert and attentive. He had significant dysarthric speech. Features included unsteady gait, nystagmus, appendicular and truncal ataxia. The ankle jerks were absent, other jerks were obtainable with enforcement. Toes were down-going. He had decrease in vibration and joint position senses distally in the toes. He had impaired gait of cerebellar type. Metabolic workup for vitamin E, B1, B6 and B12 deficiencies were not revealing. Transmission electron microscopy of the peripheral blood showed focal collections of fibrin giving finger-printing like appearance. Whole exome sequencing identified a novel homozygous mutation (c.562 T > C; p.F188 L) in the in CLN5 gene. •Our finding supports other reports of CLN-mutations associated adult-onset cerebellar ataxias.•Molecular analysis for CLN5 genes should be considered in patients presenting with adult-onset autosomal recessive cerebellar ataxia.