We report on two brothers and their maternal first cousin who have branchial arch defects and other anomalies. Similar physical findings in all three include microcephaly, downslanting palpebral fissures, highly arched palate, apparently lowset, protruding ears, bilateral hearing loss, slightly webbed neck, and mild short stature. In addition, two boys had cryptorchidism, and one had subvalvar pulmonic stenosis and body asymmetry. We suggest that these cousins have an X-linked syndrome of which branchial arch defects are a component. Other pleiotropic manifestations of the mutant gene include microcephaly and cryptorchidism; body asymmetry and relatively short stature may be components as well.