Carnitine transporter deficiency (CTD, OCTN2 deficiency) (OMIM 212140) should be considered as a primary carnitine deficiency to supply CPT I. An approximate incidence of 1:40,000 newborns has been estimated, which varies between countries, reaching 1:300 in the Faroe Islands [33]. The gene discussed is SLC22A5; the disease is hyperinsulinemic hypoglycemia, familial, 4.