AP4B1 and leukodystrophy: Five variants, ABCD1, CPT2, AP4B1, NDUFS1, and ENTPD1 (Table S2), identified using trio-WES were found to be associated with “white matter abnormalities, leukodystrophy, or very long chain fatty acid accumulation” and segregated according to the predicted genetic model (X-linked recessive, autosomal recessive, and compound heterozygote).