Familial myelodysplasia: progressive disease associated with emergency of monosomy 7.

Two brothers developed hypoplastic anaemia with the development in one of refractory anaemia with excess blasts (RAEB) accompanied by emergence of monosomy 7. Both brothers have a constitutional inversion of chromosome 1. Neither shows the increased chromosomal fragility of Fanconi's anaemia or its variants. This family is the third reported in which monosomy 7 has been found when leukaemic or preleukaemic transformation has occurred in patients with familial hypoplastic anaemia.