FINE MAPPING OF THE DYSKERATOSIS-CONGENITA LOCUS IN XQ28

Dyskeratosis congenita (DC) is characterised by reticulate skin pigmen tation, mucosal leucoplakia, and nail dystrophy. Bone marrow failure o ccurs in 50% of patients and is the principal cause of early mortality . In the majority of families the pattern of inheritance of DC is comp atible with an X linked recessive trait. The locus for the X linked re cessive form of DC has been linked to Xq28. We have now extended our e arlier studies by investigating five families with additional Xq28 pol ymorphic markers; analysis of recombinantion events in these families has located the DC1 locus between GABRA3 and DXS1108, an interval of a pproximately 4 Mb.