Gene for Simpson-Golabi-Behmel syndrome is linked to HPRT in Xq26 in two European families.

Linkage analysis was performed in 2 previously described European families segregating for the Simpson-Golabi-Behmel (SGB) syndrome. In both kindreds close linkage without recombination (zmax = 4.45 at theta = 0.00) was observed between the disease locus and the HPRT locus mapped in Xq26. These data are very similar to those (zmax = 7.5 at theta = 0.00) reported recently by others after studying a large Dutch-Canadian kindred with SGB syndrome. Compiled lod scores from the 3 families reach their maximum of 11.95 at recombination fraction of 0.00 with one lod unit support interval of 0.00-0.04.