Bloom's syndrome. Possible pitfalls in clinical diagnosis.

We treated two patients with Bloom's syndrome and conducted extensive endocrine studies. In one patient, we studied longitudinal growth and pubertal development and the effect of exogenous human growth hormone on growth velocity. Establishing a diagnosis of Bloom's syndrome is difficult in clinical practice. Measurement of the frequency of sister chromatid exchanges is essential in patients with growth retardation of intrauterine origin.