Bloom's syndrome.

Bloom's syndrome is a rare autosomal recessive disorder that characteristically shows a telangiectatic, sun-sensitive facial rash in conjunction with stunted growth. These patients are prone to respiratory and gastrointestinal infections along with immunologic abnormalities. Chromosomal aberrations include an elevated frequency of sister chromatid exchange in cultured lymphocytes, a phenomenon pathognomonic for this disorder. These patients exhibit a great tendency for neoplasia, particularly acute leukemia and lymphoma. Three cases are reported, including a follow-up of a patient diagnosed 16 years ago.