Three siblings with retinitis pigmentosa, deafness and mental retardation were studied. Physical abnormalities included nystagmus, acanthosis nigricans and multiple keloids. The two male siblings had gynecomastia, small testes and mild subvirilization whereas the only indication of hypogonadism in the female sibling was oligomenorrhea. Testosterone levels in the males, which were in the low to low normal range, were increased by the administration of large doses of chorionic gonadotropin. The two affected males had elevated plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels which were decreased by the administration of testosterone and increased by the administration of clomiphene. One sibling had mild obesity and diabetes mellitus, one had moderate obesity, normal glucose tolerance and hyperinsulinism and the third had abnormal glucose tolerance and hyperinsulinism. This familial syndrome is distinct from either the Laurence-Moon, Bardet-Biedl or Alström disorders and provides further evidence of genetic heterogeneity in this group of autosomal recessive traits.