Expression in lymphocyte and fibroblast culture of the fragile X chromosome: A new technical approach

Summary By studying those conditions most favourable for the expression of the fragile site fra(X)(q28) in lymphocytes and in fibroblasts, we have been able to develop a reliable and standardised technique. The technique which gave the best results in lymphocytes was culture in TC 199 for 96 h with addition of methotrexate 10 mg/l for the final 24 h. These same two factors, prolongation of the culture time in TC 199 and addition of methotrexate, gave satisfactory results in fibroblasts.Supported by grants from I.N.S.E.R.M. (A.T.P. 79-110)