Macrocephaly, multiple lipomas, and hemangiomata (Bannayan-Zonana syndrome): genetic heterogeneity or autosomal dominant locus with at least two different allelic forms?

We describe a boy with mild manifestations of the Bannayan-Zonana syndrome (BZS): large scaphocephalic head with marked frontal bossing, hypertrophy on the right side of the body, large and irregular café-au-lait spots, and cutaneous telangiectasia on large parts of the body and a cavernous hemangioma on the internal side of the left leg; soft cutaneous masses were present in the left axilla and inner part of the left arm; hypotonia and mild neurologic dysfunction were also present. BZS is reported as an autosomal dominant condition with variable expressivity; analysis of our data and those reported in the literature suggest that the interfamilial variability observed might represent different allelic mutations, or genetic heterogeneity.