In contrast to the rapid early-onset weight gain seen in ob/ob mice (1-3), mutations in the tub gene lead to obesity gradually and strongly resemble late-onset obesity as seen in the human population (4). In addition to excessive deposition of adipose tissue, mice with the tub phenotype also suffer retinal degeneration and neurosensory hearing loss (4-6). The tripartite character of tubby phenotype is strikingly similar to human obesity syndromes such as Alstr鰉 (5) and Bardet-Biedl (6). A c