Autosomal Recessive Spinocerebellar Ataxia Caused by a Novel Homozygous ANO10 Mutation in a Consanguineous Chinese Family

摘要

Autosomal recessive spinocerebellar ataxia (SCAR) is a clinically and genetically heterogeneous group of neurodegenerative disorders. SCAR10 caused by ANO10 mutations was first described in 2010 in a Dutch family.1 We report the first Chinese SCAR10 patient and a novel ANO10 mutation. The research was approved by the local ethics committee, and informed consent was obtained from the patient. A 41-year-old previously healthy Chinese woman born to consanguineous parents (Fig. 1A) presented with progressive gait instability and slurred speech that had first appeared 4 years previously. She experienced obvious unsteadiness when walking down stairs and turning around. No cognitive decline, psychiatric symptom, seizure, bowel or bladder dysfunction, or limb weakness was reported. A physical examination revealed dysarthria, trunk and limb ataxia, horizontal gaze-evoked nystagmus, down-beating nystagmus, hypometric saccades, brisk deep tendon reflexes, Hoffman’s sign, the Babinski sign, and ankle clonus (Supplementary Video 1 in the online-only Data Supplement). Parkinsonism, muscle wasting, fasciculation, pes cavus, and tortuosity of the conjunctival vessels were absent. Her Montreal Cognitive Assessment score was 27/30. Nerve conduction studies and electromyography produced unremarkable findings, and her electroencephalogram was normal. MRI indicated the presence of striking cerebellar atrophy (Fig. 1B and C).