Genotypes and Phenotypes of Children with SHOX Deficiency in France

Abstract

The prevalence of SHOX deficiency in children with short stature (SS) is variable in the literature and various genotypes have been identified. The aim of our study was to determine the frequency and distribution of SHOX genotypes in a large sample of children with SS in France. Children were enrolled in 38 French pediatric endocrinology centers and were either diagnosed with Leri-Weill syndrome (LWS), idiopathic short stature (ISS), or disproportionate short stature (DSS). SHOX analysis was performed centrally as part of the Genetics and Neuroendocrinology of Short Stature International Study observational study. We compared patients with (SHOX-D) and without SHOX deficiency (non-SHOX-D). Among the 537 patients tested [58.3% females, mean age 11.0 (4.2) yr], 27.7% had SHOX deficiency (LWS, 48.9%; ISS, 16.9%; DSS, 18.8%). Mean height [-2.3 (0.9) sd score] was similar in SHOX-D and non-SHOX-D patients. The majority of SHOX-D patients with LWS had either a deletion encompassing SHOX or a point mutation (69%), whereas 59% of those with ISS had a deletion downstream of SHOX in the enhancer region. The height of the parents carrying a deletion downstream of SHOX was higher than the height of the parents carrying the other gene anomalies. SHOX deletions and point mutations as well as downstream SHOX enhancer deletions were identified in almost one third of the patients tested. An anomaly in this latter region seemed to be linked to a milder phenotype. Although further confirmation is needed, we suggest that the enhancer region should be systematically analyzed in patients suspected of SHOX deficiency.