In four patients, rare heterozygous RDVs were detected in other neurodegeneration-associated genes, such as PRKN (PD), LRRK2 (PD), PARK7 (PD), C19ORF12 (NBIA), SPG11 (Spastic paraplegia-SP/ALS), and PSAP (Metachromatic leukodystrophy-MLD) (Table 5). The gene discussed is PSAP; the disease is neurodegeneration with brain iron accumulation.