Clinical and molecular characterization of Chilean patients with Léri-Weill dyschondrosteosis

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.

SHOX gene and conserved noncoding element deletions/duplications in Colombian patients with idiopathic short stature

SHOX gene mutations or haploinsufficiency cause a wide range of phenotypes such as Leri Weill dyschondrosteosis (LWD), Turner syndrome, and disproportionate short stature (DSS). However, this gene has also been found to be mutated in cases of idiopathic short stature (ISS) with a 3–15% frequency. In this study, the multiplex ligation-dependent probe amplification (MLPA) technique was employed to determine the frequency of SHOX gene mutations and their conserved noncoding elements (CNE) in Colombian patients with ISS. Patients were referred from different centers around the county. From a sample of 62 patients, 8.1% deletions and insertions in the intragenic regions and in the CNE were found. This result is similar to others published in other countries. Moreover, an isolated case of CNE 9 duplication and a new intron 6b deletion in another patient, associated with ISS, are described. This is one of the first studies of a Latin American population in which deletions/duplications of the SHOX gene and its CNE are examined in patients with ISS.