Finally, screening for certain disorders such as Organic Cation Transporter 2 deficiency (OCTN2 deficiency, see Box 1C) (11, 12) might detect mildly affected or asymptomatic mothers, because abnormal biomarkers in the neonate can be caused by an aberrant biochemical profile in the mother. This evidence concerns the gene SLC22A5 and hyperinsulinemic hypoglycemia, familial, 4.