SLC33A1 and muscular atrophy: Race-related heterozygous mutation in the Solute Carrier Family 33 Member 1 (SPG42/SLC33A1) in Chinese lineages with haploinsufficiency [23] at 3q25.31 shows classical signs of hyperreflexia, lower extremity muscular atrophy, and pes cavus at varying ages from 4 to 42 but predominately around 20 years.