Other examples include mutations in PRKAG2 (AMP‐activated protein kinase) associated with Wolff–Parkinson–White syndrome (Gollob et al, 2001), and glycogen storage diseases such as Pompe disease (a recessive lysosomal acid α‐1,4‐glucosidase deficiency), Fabry disease (X‐linked lysosomal hydrolase α‐galactosidase A deficiency) and Danon disease (X‐linked lysosome‐associated membrane protein 2 (LAMP2) deficiency) (Ahmad et al, 2005). The gene discussed is PRKAG2; the disease is hyperinsulinemic hypoglycemia, familial, 4.