Similarly, genetic testing for spinocerebellar ataxia (SCA 18 & 20), hereditary spastic paraparesis type 7 (caused by SPG 7 gene mutation), Alexander’s disease (glial fibrillary acid protein) and POLG mutation (mitochondrial disorders) can be helpful in reference to familial PAPT [43, 58, 60, 61, 63, 64, 65]. Here, POLG is linked to Alexander disease.