Identification of IFRD1 variant in a Han Chinese family with autosomal dominant hereditary spastic paraplegia associated with peripheral neuropathy and ataxia.

Spinocerebellar ataxias (SCAs) are a group of autosomal dominant, clinically heterogeneous neurodegenerative disorders. SCA18 is a rare autosomal dominant sensory/motor neuropathy with ataxia (OMIM#607458) associated with a single missense variant c.514 A>G in the interferon related developmental regulator 1 (IFRD1) gene previously reported in a five-generation American family of Irish origin. However, to date, there have been no other reports of the IFRD1 mutation to confirm its role in SCA. Here, we report a Han Chinese family with SCA18; the family members presented with a slowly progressing gait ataxia, pyramidal tract signs, and peripheral neuropathy. We identified a missense variant (c.514 A>G, p.I172V) in IFRD1 gene in the family using targeted next-generation sequencing and Sanger direct sequencing with specific primers. Our results suggest that the IFRD1 gene may be the causative allele for SCA18.