While SPG7 biallelic mutations have historically been associated with HSP, it is now clear that ataxia is the major clinical presentation, as only 26% of our cohort presented with an HSP-like phenotype.7,14,15 In another UK-based study, SPG7 accounted for 18.6% of 70 patients with unexplained ataxia and pyramidal signs.7SPG7 is the fourth commonest cause of any genetic ataxia in the United Kingdom and the second commonest recessive ataxia.16 In support of this finding, 90% of our SPG7 cohort demonstrated gait ataxia with cerebellar dysarthria (table 2). The gene discussed is SPG7; the disease is cerebellar ataxia.