Association of CTG repeat polymorphism in carnosine dipeptidase 1 (CNDP1) gene with diabetic nephropathy in north Indians.
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Date
2016-07
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Abstract
Background & objectives: CNDP1 gene, present on chromosome 18q22.3-23, encodes carnosinase, the rate-limiting enzyme in hydrolysis of carnosine to β-alanine and L-histidine. Linkage of CTG trinucleotide (leucine) repeat polymorphism in CNDP1 gene with diabetic nephropathy has been observed in several populations. However, this association is conflicting and population-dependent. We investigated this association in type 2 diabetes mellitus (T2DM) patients with and without nephropathy in north India.
Methods: A total of 564 individuals [199 T2DM without nephropathy (DM), 185 T2DM with nephropathy (DN) and 180 healthy individuals (HC)] were enrolled. CNDP1 CTG repeat analysis was done by direct sequencing of a 377 base pair fragment in exon 2.
Results: The most frequent leucine (L) repeats were 5L-5L, 6L-5L and 6L-6L. 5L-5L genotype frequency was reduced in DN (24.3%) as compared to DM (34.7%, P=0.035) and HC (38.4%, P=0.005). Similarly, 5L allele frequency was lower in DN (46.8%) as compared to DM (57.3%, P=0.004) and HC (60.5%, P<0.001). The genotype and allelic frequencies were similar in DM and HC groups. No gender specific difference was observed in the genotype or allelic frequencies between groups.
Interpretation & conclusions: Compared to healthy individuals and those with diabetes but no kidney disease, patients with diabetic nephropathy exhibited lower frequencies of 5L-5L genotype and 5L allele of CNDP1 gene, suggesting that this allele might confer protection against development of kidney disease in this population.
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Keywords
Carnosinase, CNDP1, CTG repeat, diabetic nephropathy, genetics, genotype, type 2 diabetes
Citation
Yadav Ashok K, Sinha Nisha, Kumar Vinod, Bhansali Anil, Dutta Pinaki, Jha Vivekanand. Association of CTG repeat polymorphism in carnosine dipeptidase 1 (CNDP1) gene with diabetic nephropathy in north Indians. Indian Journal of Medical Research. 2016 July; 144(1): 32-37.