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 leucoplak ia. Bone marrow failure occurs in the majority of cases and there is a predisposition to malignancy. Following conflicting reports of increa sed 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 clast ogenic agents and gamma-irradiation. There was no significant differen ce in the chromosomal breakage in DC lymphocytes with or without expos ure to bleomycin, DEB, MMC or gamma-irradiation. DC can therefore be d istinguished from Fanconi's anaemia in which lymphocytes show increase d spontaneous and clastogen-induced chromosomal breakage.