Chromosomal breakage analysis in dyskeratosis congenita peripheral blood lymphocytes.

Dyskeratosis congenita (DC) is a rare inherited disorder characterized by reticulate skin pigmentation, nail dystrophy and mucosal leucoplakia. Bone marrow failure occurs in the majority of cases and there is a predisposition to malignancy. Following conflicting reports of increased spontaneous and induced chromosomal breakage in DC lymphocytes, we examined chromosomal breakage with and without clastogen treatment in 10 DC patients from six different families. Peripheral blood cultures were stimulated with phytohaemagglutinin and treated with three clastogenic agents and gamma-irradiation. There was no significant difference in the chromosomal breakage in DC lymphocytes with or without exposure to bleomycin, DEB, MMC or gamma-irradiation. DC can therefore be distinguished from Fanconi's anaemia in which lymphocytes show increased spontaneous and clastogen-induced chromosomal breakage.