PTRHD1 and Intellectual disability: Homozygous missense mutations and 28-nucleotid frameshift deletion in PTRHD1 (peptidyl-tRNA hydrolase domain-containing 1, MIM*617342) have been recently identified in two unrelated consanguineous Iranian families and in a sub-Saharan African kindred with early onset Parkinsonism and intellectual disability (150, 151).