The two infants with carnitine‐acylcarnitine translocase (CACT) or carnitine palmitoyltransferase II (CPTII) deficiency had a severe phenotype, and 27% of HM‐fed infants with MCAD deficiency were symptomatic at diagnosis (n = 13/48) (Table S2). The gene discussed is SLC25A20; the disease is medium chain acyl-CoA dehydrogenase deficiency.