AT‐related disorder

Abstract

Two sisters with a complex clinical pattern, including microcephaly, microgenia, defects of skin pigmentation, anal stenosis/atresia, and combined immunodeficiency together with spontaneous chromosomal instability and cellular hypersensitivity to X‐rays and bleomycin are described. Complementation studies on heterokaryons proved that the underlying genetic defect is non‐allelic with that of patients with ataxia telangiectasia (complementation groups AB‐E) and the Nijmegen breakage syndrome, but identical with the case described by Conley et al. (1986).