Bikunin and α1-microglobulin/bikunin precursor (AMBP) gene mutational screening in patients with kidney stones: a case-control study.
OBJECTIVE
Bikunin is an inhibitor of kidney stone formation synthesized in the liver together with α(1)-microglobulin from the α(1)-microglobulin/bikunin precursor (AMBP) gene. The aim of this study was to investigate the possible association between bikunin/AMBP gene polymorphisms and urinary stone formation.


METHODS
To analyse the DNA, blood samples were taken from 75 kidney stone formers who had a familial stone history, 35 sporadic stone formers and 101 healthy individuals. Four exons of bikunin gene and five parts of the promoter region of the AMBP gene were screened using single-strand conformation polymorphism and nucleotide sequence analysis.


RESULTS
The Init-2 region of the promoter of AMBP gene had polymorphisms at positions -218 and -189 nt giving three different genotypes having 1,3, 2,4 and 1,2,3,4 alleles with frequencies of 17.06%, 60.19% and 22.75%, respectively, in all groups. Therefore, the Init-2 region appears to be polymorphic. As a result, the 1,3 allele has -218G and -189T complying with the reference database sequence, the 2,4 allele has -218G and T-189C substitution and the allele 1,2,3,4 genotype has substitutions at positions G-218C and T-189C.


CONCLUSIONS
There were no significant differences in allele distribution between patients and controls. These common alleles exist in the Turkish population independent of stone formation. These results are the first to demonstrate the existence of bikunin and AMBP promoter polymorphism. Although the Init-2 region of the AMBP gene is the binding site for various transcription factors, the results showed no association between these observed genotypes and stone-forming phenotypes.
Igci
Mehri
M
Department of Medical Biology, Faculty of Medicine, University of Gaziantep, Gaziantep, Turkey. mehriigci@gmail.com
Arslan
Ahmet
A
Igci
Yusuf Ziya
YZ
Gogebakan
Bulent
B
Erturhan
M Sakip
MS
Cengiz
Beyhan
B
Oztuzcu
Serdar
S
Cakmak
Ecir Ali
EA
Demiryurek
A Tuncay
AT
D000293:Adolescent; D000328:Adult; D000483:Alleles; D000510:Alpha-Globulins / Q000235:genetics*; D016022:Case-Control Studies; D005091:Exons; D005260:Female; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D007669:Kidney Calculi / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D014421:Turkey; D055815:Young Adult
D000510:Alpha-Globulins; C016001:alpha-1-microglobulin