Encouraging data in preclinical animal models and in clinical trials [reviewed in (30)] have led to the approval of several gene therapies in recent years, starting with Glybera, a rAAV1 carrying the lipoprotein lipase gene, whose intramuscular delivery aimed at the treatment of lipoprotein lipase deficiency. Here, LPL is linked to hyperinsulinemic hypoglycemia, familial, 4.