Lack of an association between GHR exon 3 polymorphism and diabetic nephropathy in the Genetics of Kidneys in Diabetes (GoKinD) population

Excerpt

To the Editor: Growth hormone (GH) signalling via the GH receptor (GHR) forms the GH/GHR axis and plays an important role in metabolism. There is a genomic deletion of full-length exon 3 (d3 isoform) in the GHR gene. Previously, the GHRd3 isoform is found to be significantly associated with increased responsiveness to growth hormone [1]. Although the consensus is lacking in subsequent studies [2], GHRd3 has also been found to be associated with hypertension among stroke patients [3]. Recently, a report from our research group has demonstrated that the homozygosity for the GHRd3 allele may have the protective effect on the prevalence of type 2 diabetes [4]. Furthermore, evidence has suggested that the glomerular podocyte is a target for GH action, and the GH/GHR axis may play a role in the development of diabetic nephropathy (DN) [5, 6]. A recent study has shown that deficiency of GHR in mice (Ghr knockout) causes a reduction in systolic blood pressure and plasma renin levels, as well as an increase in aortic endothelial NO synthase (eNOS) levels [7]. We thus hypothesise that GHR exon 3 polymorphism may be involved in the pathogenesis of DN. …