We describe nine patients with an apparently new genetic disorder characterized by:
1) microcephaly with normal intelligence;
2) 'bird'-like facial appearance;
3) cellular and humoral immune defects; and
4) increased risk for lymphoreticular malignancies. The postmortem findings of five patients are described. Chromosome instability appears not to be a component of the disorder. The occurrence in three pairs of sibs and isonomy in another family suggests autosomal recessive inheritance.