Familial myelodysplastic syndrome with onset late in life.

A family is described in which three, and possibly four members, namely, the propositus, two paternal uncles, and possibly his paternal grandfather, developed a myelodysplastic syndrome (MDS) after the age of 60 years. This late onset resembles sporadic cases which are commoner in older age, rather than the previously reported familial cases most of whom have been children or young adults. The three affected members had megaloblastoid bone marrows with an increased proportion of bone marrow blasts and developed progressive bone marrow failure without leukemic transformation. The propositus showed a dramatic but temporary response to GM-CSF therapy but eventually became unresponsive with a marked increase in bone marrow reticulin and reduction in hemopoietic elements. Affected members had no recognisable bone marrow cytogenetic abnormality but the pattern of inheritance and similarity in clinical features suggest an inherited genetic defect which predisposes to the development of MDS.