Close linkage of hypervariable marker DXS255 to disease locus of Wiskott-Aldrich syndrome.

Linkage analyses in 5 families with Wiskott-Aldrich syndrome show that a novel hypervariable locus, DXS255, is very closely linked to the disease gene on the proximal short arm of the X chromosome. DXS255, with a maximum lod score of 5.42 at theta = 0.00 (90% confidence interval 0.00, 0.10) and heterozygosity of over 90%, is likely to be the closest available marker to the Wiskott-Aldrich gene and to be helpful in genetic counselling of affected families.