Mapping of the second locus for the Van der Woude syndrome to chromosome 1p34

The Van der Woude syndrome (VWS) is a dominantly inherited developmental disorder characterized by pits and/or sinuses of the lower lip, cleft lip and/or cleft palate. It is the most common cleft syndrome. VWS has shown remarkable genetic homogeneity in all populations, and so far, all families reported have been linked to 1q32-q41. A large Finnish pedigree with VWS was recently found to be unlinked to 1q32-q41. In order to map the disease locus in this family, a genome wide linkage scan was performed. A maximum lod score of 3.18 was obtained with the marker D1S2797, thus assigning the disease locus to chromosomal region 1 p34. By analyses of meiotic recombinants an similar to 30 cM region of shared haplotypes was identified. The results confirm the heterogeneity of the VWS syndrome, and they place the second disease locus in 1p34. This finding has a special interest because the phenotype in VWS closely resembles the phenotype in non-syndromic forms of cleft lip and palate.