Editor—The original report by Robinow and Sorauf1 described a large family with autosomal dominant craniosynostosis and hallucal duplication. The clinical features include craniosynostosis, plagiocephaly, flat face, hypertelorism, thin, long, and pointed nose, shallow orbits, strabismus, and broad great toes with a duplication of the distal phalanx. This autosomal dominant syndrome is listed as a separate entry in the McKusick catalogue2 (MIM 180750), although it is clinically similar to Saethre-Chotzen syndrome (MIM 101400). The most characteristic additional feature in Robinow-Sorauf syndrome is a bifid or partially duplicated hallux. In the past, the relationship between these conditions has been controversial. Carter et al 3 emphasised the differences in the phenotype in two patients, and considered it as a separate entity in accordance with the report of Robinow and Sorauf.1 In a further report, similar clinical findings were described as Saethre-Chotzen syndrome4 or an unusual form of acrocephalosyndactyly.5 Another phenotypically similar phenotype has been described as Pfeiffer syndrome.6 Bifid distal hallucal phalanges have also been observed in auralcephalosyndactyly syndrome, in which brachycephaly, facial asymmetry, delayed suture closure, and small pinnae were associated with cutaneous syndactyly 4/5 of the feet.7 8 Based on the cytogenetic findings of Reardon and Winter9 involving chromosome 7p21, there is now growing consensus that Robinow-Sorauf syndrome is a variant of Saethre-Chotzen syndrome involving the same gene.

Recently, mutations in the gene TWIST have been identified in patients with Saethre-Chotzen syndrome.10-12 The gene is localised on chromosome 7p21 and encodes a transcription factor containing a basic …