Association of Growth Hormone Receptor Gene Variants with Mandibular Form in an Egyptian Population

A signi cant genetic component is involved in the development of the craniofacial form. Recently, the growth hormone receptor gene (GHR) variants rs6180 and rs6184 were associated with variations in mandibular form. To con rm these ndings we evaluated the relationship between these GHR variants and mandibular form in a cohort of Egyptian individuals with a normal skull form. The patients consisted of 191 unrelated Egyptian adults (92 males, 99 females ; 18-55 years). Allele frequencies of the rs6180 and rs6184 variants were determined from genomic DNA extracted from saliva using the Taqman genotyping assay. Lateral and posteroanterior cephalometric tracings were used to obtain 19 mandibular measurements. The association between the GHR variants and the mandibular measurements was examined using regression analysis. The frequency of the minor rs6184 variant was very low at 1.5% : therefore, association studies were not performed for this variant. The rs6180 variant was not associated with any of the measurements representing mandibular form in our study cohort. The frequency of the rs6184 variant was very low in our cohort of Egyptian subjects. We also found no association between the rs6180 variant and the measurements representing the mandibular form. By excluding the involvement of these GHR variants in in uencing mandibular form, our results may help to identify the actual variant (s) affecting the mandibular form in the Egyptian population.