DMD and hyperinsulinemic hypoglycemia, familial, 4: It is possible for a second mutation to introduce underlying biochemical or biological differences however, for example utrophin−/− single transgenic mice have an increased susceptibility to seizures (Knuesel et al, 2002), along with altered neuromuscular junction folding and altered acetyl choline receptor density (Grady et al, 1997a), which could feasibly affect neuromuscular disease outside of a direct consequence of dystrophin deficiency (Willmann et al, 2009).