Gene localisation of X-linked hypohidrotic ectodermal dysplasia (C-S-T syndrome).

Genetic linkage studies were carried out in families with X-linked hypohidrotic ectodermal dysplasia (C-S-T syndrome). A DNA probe DXYS1 (pDP34), which maps both to the proximal part of the long arm of the X chromosome, Xq13-Xq21, and proximally on Yp, was used to detect a TaqI restriction fragment length polymorphism of the X-chromosomal locus in the DNA samples from 11 families. This locus was found to be closely linked to the X-linked hypohidrotic ectodermal dysplasia locus, with a lod score of 2.66 at recombination fraction (theta) of 0.06 (90% confidence limits 0.01-0.26). Only one crossover was observed in nineteen meioses. This indicates that the probe DXYS1 is closely linked to the X-linked hypohidrotic ectodermal dysplasia locus and is likely to facilitate carrier detection and prenatal diagnosis tests.