PMPCA and Autosomal recessive cerebelloparenchymal disorder type 3: Conversely, pathogenic mutations within the PMPCA regulatory subunit contribute to autosomal recessive spinocerebellar ataxia-2 (SCAR2, MIM #213200), a non-progressive neurological disorder characterised by intellectual disability, dysarthria, loss of fine motor skills and ataxic gait [19].