Intermittent 20q- and consistent i(7q) in a patient with Shwachman-Diamond syndrome.

Shwachman Diamond syndrome (SDS) is a genetic disorder characterized by pancreatic hypoplasia, recurrent infection and bone marrow dysfunction. Some cases have an abnormality of chromosome 7, such as isochromosome 7q (i(7q)), which may be associated with the development of leukemia. We present a boy who was diagnosed with SDS at 19 months of age. From age 5-14 years, bone marrow cytogenetics has shown a consistent abnormality - i(7q), with an intermittent separate abnormality - deletion 20q, from age 11 years. During this time, the boy has been clinically well without leukemic signs, managed conservatively. We suggest that deletion 20q may be a non random secondary change in SDS with i(7q).