Evidence for the location of the Saethre-Chotzen acrocephalosyndactyly mutation on 7p21-22 is based on genetic linkage studies in families segregating for this autosomal dominant disorder. Linkage studies were guided by several reports of chromosome deletions in this region giving rise to craniosynostosis and some other manifestations of Saethre-Chotzen syndrome. We report on a family where a father and daughter carry an apparently balanced t(7;10)(p21.2;q21.2) translocation (de novo in the father) and have the Saethre-Chotzen syndrome. These observations support the localization of the Saethre-Chotzen gene to 7p21.2.