We describe a family segregating an autosomal dominant mutation producing a syndrome comprising microcephaly with normal intelligence and short palpebral fissures together with variable signs including thumb hypoplasia, shortness of the middle phalanges of the second and fifth fingers, small feet, a gap between the first and second toes, and mild syndactyly of the toes or fingers. A characteristic radiologic finding in our family is thinning of the proximal end of the first metacarpal and shortening of that metacarpal. The severity of these findings was asymmetric in our patients. This syndrome is similar to patients described by Brunner and Winter [1991: J Med Genet 28: 389-394], Feingold [1975: Synd Ident 3:16-17, 1978: Hosp Prac 13:44-49], and König et al. [1990: Dysmorphol Clin Genet 4:83-86].