Background: PraderWilli syndrome (PWS) is a genomic imprinting disorder due to loss of paternally expressed genes in the 15q11q13 region and characterized by hypotonia, a poor suck, hypogonadism, GH deficiency(GHD), learning and behavioural problems. GH acts as a ligand for the GH receptor (GHR) coded by a gene polymorphism for an exon-s deletion (d3) seen in about 50% of Caucasians and associated with an increased response to GH (GH) therapy.
Objective and hypotheses: We designed the present study by analyzing those polymorphisms in Chinese PWS patients. By comparing our results with previous studies, we aimed to identify the association between the effect of recombinant human GH (rhGH) and genetic polymorphism in Chinese PWS patients.
Method: We designed the present retrospective study involved 57 PWS patients diagnosed genetically. We used a multiplex PCR method for the genotyping of polymorphisms in exon 3 of GHR gene. We then compared out genotype results with data from previous studies on patients with obesity or short stature.
Results: In our PWS patient cohort, the genotype frequencies of fl/f, fl/d3, and d3/d3 in GHR exon 3 (70%, 23%, and 7% respectively) were not different from general population in Chinese. However the frequencies of d3/d3 and fl/d3 genotype were lower than European general population. We did not find difference between genotype distribution when compared either with patients with idiopathic short stature and Turner syndrome or with patients with obesity and overweight. However, difference in genotype distribution was found in comparison with GHD patients.
Conclusion: No differences in distribution of GHR exon 3 polymorphisms were found between Chinese PWS patients and general population. Less common phenotype of short stature manifested among Chinese PWS patients could be due to the lower frequence of d3 genotype in GHR gene.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology