A Deletion of More than 800 kb Is the Most Recurrent Mutation in Chilean Patients with SHOX Gene Defects.

BACKGROUND

Deletions in the SHOX gene are the most frequent genetic cause of Leri-Weill syndrome and Langer mesomelic dysplasia, which are also present in idiopathic short stature.

AIM: To describe the molecular and clinical findings observed in 23 of 45 non-consanguineous Chilean patients with different phenotypes related to SHOX deficiency.

METHODS

Multiplex ligation-dependent probe amplification was used to detect the deletions; the SHOX coding region and deletion-flanking areas were sequenced to identify point mutations and single-nucleotide polymorphisms (SNPs).

RESULTS

The main genetic defects identified in 21 patients consisted of deletions; one of them, a large deletion of >800 kb, was found in 8 patients. Also, a smaller deletion of >350 kb was observed in 4 patients. Although we could not precisely determine the deletion breakpoint, we were able to identify a common haplotype in 7 of the 8 patients with the larger deletion based on 22 informative SNPs.

CONCLUSION

These results suggest that the large deletion-bearing allele has a common ancestor and was either introduced by European immigrants or had originated in our Amerindian population. This study allowed us to identify one recurrent deletion in Chilean patients; also, it contributed to expanding our knowledge about the genetic background of our population.