Only 19 infants (8.5%) were symptomatic at the time of the NBS result (1 LCHADD, 5 PA, 1 CPT‐II, 1 MMA, 3 MMAHC, 2 MSUD, 2 OTC deficiency, 1 CTLN1, 1 MCADD, 2 TYR‐1), displaying different clinical presentations and evolutions (Table 2). This evidence concerns the gene ASS1 and hyperinsulinemic hypoglycemia, familial, 4.