Hypoinsulinemic hypoglycemia with hemihypertrophy (HIHGHH) [OMIM#240900] is characterized by recurrent severe fasting hypoglycemia and asymmetrical growth.
AKT2 [OMIM#164731] encodes for a serine/threonine kinase. Hussain et al. (2011) identified the same de novo missense mutation in three patients with the HIHGHH phenotype. In one patient the mutation was identified in the mosaic state. The mutation identified was an activating mutation, and functional studies showed it lead to insulin-independent activation of downstream signaling.