A boy with congenital malformations and chromosome breakage.

A patient with increased chromosome breakage and multiple congenital malformations is described. The lack of any apparent quantitative or qualitative disturbance in hemopoiesis and adequate number of myeloid and erythroid progenitor cells and the absence of certain clinical features such as webbed neck and absence of dark pigmentation in the patient did not support the diagnosis of the Fanconi pancytopenia syndrome. The cytogenetic studies revealed increased chromosome breakage at G1 phase, a finding which is also at variance with that observed in patients with the Fanconi pancytopenia syndrome.