Crouzon syndrome (MIM 123500) is a common autosomal dominant form of craniosynostosis with shallow orbits, ocular proptosis, and maxillary hypoplasia. Jackson-Weiss syndrome (MIM 123150) is another autosomal dominant craniosynostosis with highly variable phenotypic expression. Unlike Crouzon syndrome, Jackson-Weiss syndrome is associated with foot anomalies. We performed two point linkage and haplotype analyses using 13 dinucleotide repeat markers on chromosome 10, spanning a genetic distance of 108 cM. The Crouzon syndrome locus (CFD1) maps to the region of chromosome 10q2, with the tightest linkage to locus D10S205 (Z = 3.09, theta = 0.00). the Jackson-Weiss syndrome locus in the large Amish pedigree in which the condition was originally described was also linked to the chromosome 10q23-q26 region between loci D10S190 and D10S186. The D10S209 locus was most strongly linked (Z = 11.29, theta = 0.00).