A novel PNPLA6 mutation in a Turkish family with intractable Holmes tremor and spastic ataxia.

Autosomal recessive cerebellar ataxias are a group of rare neurological diseases with a genetic origin. Recently, the mutations in the PNPLA6 gene were suggested to lead to ataxia and also to other specific syndromes such as Boucher-Neuhauser (ataxia, hypogonadism, and chorioretinal dystrophy) or Gordon-Holmes Syndromes (ataxia, hypogonadism, and brisk reflexes) within a broad spectrum of neurodegenerative diseases. Here we report three patients from a single-family with a novel pathogenic mutation in the PNPLA6 gene which led to predominantly spastic-ataxia, and intractable Holmes tremor. The PNPLA6-related disease should be considered in the differential diagnosis of spastic-ataxias even in the absence of chorioretinal dystrophy, and hypogonadotropic hypogonadism. Further studies should unravel the factors which account for the phenotypic variability present in patients with PNPLA6 gene mutations.