Coronal craniosynostosis, hypertelorism, telecanthus, broad grooved nasal tip, dental anomalies, mild syndactyly and broad thumbs, consistent with craniofrontonasal dysplasia are described in a family of four affected females over three generations. Documentation of the family is of interest because of variable clinical features and an excess of affected females. The excess of females observed in this condition is as yet unexplained, but cannot be referred simply to X-linked dominance with lethality in the male. Autosomal dominance with less frequent and less severe expression in the male is more tenable. Chromosome analysis on two affected family members revealed a fragile site at 12q13, which was also found in a phenotypically normal family member. A third affected individual did not exhibit this fragile site. Thus it appears that there is a heritable fragile 12q13 site segregating in this family separately from the gene for craniofrontonasal dysplasia.