Sequence analysis of the Utah affected family indicates that both the proband and his brother inherited the SLC27a6294 allele from their father; thus, if causative of leukodystrophy, mutation of SLC27a6 leads to an incompletely penetrant leukodystrophy (and, as for ABCD1, another member of the fatty acid metabolic pathway, disease risk is enhanced by additional genetic and/or environmental factors). Here, SLC27A6 is linked to leukodystrophy.