Diagnostic workup may include measuring enzymatic activity in skeletal muscle biopsy, assessing serum acylcarnitine profiles showing increased C12 to C18 acylcarnitine levels and specifically (C16 + C18:1)/C2 ratio, highly suggestive of CPT2 deficiency [13]. Here, CPT2 is linked to hyperinsulinemic hypoglycemia, familial, 4.