Simultaneous occurrence of diabetes mellitus, diabetes insipidus, and optic atrophy in a brother and sister.

We report the cases of two siblings who died at age 21 and 15 years respectively. Both had optic atrophy, pitressinsensitive diabetes insipidus, and insulin-dependent diabetes mellitus, with onset occurring in early childhood. Although there are now 21 patients from 15 families with this syndrome, this is the first time that necropsy findings have become available. They include the expected atrophy of hypothalamic nuclei and degeneration of the optic nerves, chiasm and tract, as well as a totally unexpected degeneration of the pons and cerebellum.