CPT2 and hyperinsulinemic hypoglycemia, familial, 4: Because the accumulation of acylcarnitines indicative of FAODs tends to be smaller in well-fed states, sampling of DBS on postnatal day 4 or 5 may be late for some patients with milder phenotypes, which appears to be especially true of CPT II deficiency in comparison with VLCAD deficiency, for which NBS can identify many newborns with the mildest disease [14].