Tuberous sclerosis: aberrant proline sensitivity of skin fibroblasts

Cultured skin fibroblasts from patients with tuberous sclerosis were analyzed as to their sensitivities to proline, glutamic acid and arginine, and their analogues by means of a cell growth study. A difference was observed between tuberous sclerosis and normal cells when proline was added. Skin fibroblasts derived from normal-appearing skin of tuberous sclerosis patients exhibited sensitivity to proline. Skin fibroblasts derived from tumorous skin of tuberous sclerosis patients exhibited resistance to proline in the cell growth study and was found to be rather sensitive to proline in a colony formation study. This aberrant sensitivity to proline of tuberous sclerosis cells may indicate abnormal proline metabolism in tuberous sclerosis patients.