Increased independent ingestion in Anorexia (anx) mutant mice

Anorexia mutant mice (anx/anx) stop gaining weight by postnatal day 14 and die from starvation within 3-4 weeks. Their defect is not conclusively identified: a point mutation in Tyro3 is present and modulates the phenotype. The behavioral or physiological mechanisms causing starvation are unknown. To determine if anx causes decreased independent ingestion, pups were given short-term access to half-and-half on postnatal days 14 and 19. The anx mutants ingested similar or larger amounts than wildtype on both days. The anx/anx mutation may decrease growth not by hypophagia per se, but as result of other complications such as decreased maternally-dependent suckling or failure to transition to independent ingestion.