Del(20q) Deletion

Deletions of the long arm of chromosome 20 are found in 4.1% and 1.5% of MDS and AML cases respectively. Del(20q) also occurs in 10% of polycythemia vera patients and other subgroups of MPD. Due to the relatively small size of the deletion and the lack of banding features on chromosome 20, FISH is particularly useful in detecting this abnormality. The prognosis for MDS cases where del(20q) is the sole abnormality is good. However if secondary abnormalities are present, a poor outcome is indicated. AML patients respond poorly to treatment and have reduced survival rates. The clinical outcome for MPD patients remains unchanged in the presence of the abnormality.