Deficient DNA repair in human progeroid cells.

Skin fibroblasts biopsied from a patient with clinical symptoms of the Hutchinson-Gilford progeria syndrome failed to show evidence of normal DNA strand rejoining in vitro after exposure to cobalt-60 gamma irradiation. Control human diploid fibroblasts of fetal origin in early passage, skin fibroblasts of adult origin, and an established line of human liver cells (LICH) all showed essentially complete rejoining of radiation-induced strand breaks within 30 min after irradiation, as evidenced by DNA sedimentation profiles in alkaline sucrose gradients. The results suggest that an enzyme involved in DNA repair may be absent or greatly reduced in efficiency in cells from this patient with the progeria syndrome. Such a repair-deficient cell strain may prove useful in the study of the molecular events associated with x-ray-type damage and its repair in mammalian cells.