Genetic variation at selected SNPs in the leptin gene and association of alleles with markers of kidney disease in a Xhosa population of South Africa.
BACKGROUND
Chronic kidney disease (CKD) is a significant public health problem that leads to end-stage renal disease (ESRD) with as many as 2 million people predicted to need therapy worldwide by 2010. Obesity is a risk factor for CKD and leptin, the obesity hormone, correlates with body fat mass and markers of renal function. A number of clinical and experimental studies have suggested a link between serum leptin and kidney disease. We hypothesised that variants in the leptin gene (LEP) may be associated with markers of CKD in indigenous black Africans.


RESULTS
Black South Africans of Xhosa (distinct cultural Bantu-speaking population) descent were recruited for the study and four common polymorphisms of the LEP (rs7799039, rs791620, rs2167270 and STS-U43653 [ENSSNP5824596]) were analysed for genotype and haplotype association with urine albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), Serum creatinine (Scr) and serum leptin level. In one of the four single nucleotide polymorphisms (SNPs) we examined, an association with the renal phenotypes was observed. Hypertensive subjects with the T allele (CT genotype) of the ENSSNP5824596 SNP had a significantly higher eGFR (p = 0.0141), and significantly lower Scr (p = 0.0137). This was confirmed by haplotype analysis. Also, the haplotype GAAC had a modest effect on urine albumin-to-creatinine ratio in normotensive subjects (p = 0.0482).


CONCLUSIONS
These results suggest that genetic variations of the LEP may be associated with phenotypes that are markers of CKD in black Africans.
Okpechi
Ikechi G
IG
Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa. ikokpechi@yahoo.com
Rayner
Brian L
BL
van der Merwe
Lize
L
Mayosi
Bongani M
BM
Adeyemo
Adebowale
A
Tiffin
Nicki
N
Ramesar
Rajkumar
R
D000328:Adult; D000419:Albuminuria / Q000652:urine; D000483:Alleles; D001483:Base Sequence; D044383:Black People / Q000235:genetics; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D005919:Glomerular Filtration Rate; D006239:Haplotypes; D006801:Humans; D006973:Hypertension / Q000150:complications; D007674:Kidney Diseases / Q000150:complications / Q000208:ethnology / Q000235:genetics*; D020738:Leptin / Q000097:blood / Q000235:genetics*; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D013019:South Africa
D020738:Leptin; D003404:Creatinine