SPNS1 and hereditary disease: The variant in SPNS1 was by far the most likely candidate, as 3 of the 5 mutations have been reported in homozygous form in gnomAD (Supplemental Table 1), which removes pediatric genetic disease cases, and the only other remaining mutation is not considered likely to be pathological by 3 bioinformatic programs: SIFT, CADD, and REVEL (Supplemental Table 1).