Mapping the gene responsible for Smith-Fineman-Myers syndrome to Xq25

Objective. To map and eventually identify the gene responsible for Smith-Fineman-Myers syndrome. Methods. The short tandem repeat markers (STRs) distributed on X chromosome at 8-10cM interval were used in the initial mapping to look for the candidate region for Smith-Fineman-Myers syndrome locus and the linked marker. The additional STRs flanking the linked marker were tested to confirm the candidate region and decide the interval of disease gene. Results. Thirteen DNA samples from a Chinese family with Smith- Fineman-Myers syndrome were genotyped using 20 polymorphic STRs which cover the whole X chromosome. Of 20 STRs, DXS1001 on Xq25 suggested linkage and yielded a lod score of 3.01 at θ=0, additional STRs flanking DXS1001 were tested. Fourteen polymorphic STRs out of 27 confirmed that Smith-Fineman- Myers syndrome locus is linked to several markers on Xq25. Haplotype analysis placed the disease locus within a 14. 6 cM interval bounded by DXS8064 and DXS8050. Conclusion. The gene responsible for Smith-Fineman-Myers syndrome is mapped to a 14. 6 cM interval between DXS8064 and DXS8050 on Xq25. This result will be helpful for the identification of disease gene.