Insulin-like growth factor I gene microsatellite repeat, collagen type Ialpha1 gene Sp1 polymorphism, and bone disease in primary biliary cirrhosis.
BACKGROUND
Genetic factors have been implicated in the pathogenesis of osteoporosis, a common disorder in primary biliary cirrhosis. Insulin-like growth factor I (IGF-I) gene microsatellite repeat polymorphism was found to be associated with osteoporosis in some studies, and collagen-Ialpha1 (COLIA1) Sp1 s allele was associated with lower bone mineral density in primary biliary cirrhosis. IGF-I treatment restored osteopenia and reduced fibrogenesis in experimental cirrhosis. We investigated IGF-I and COLIA1 gene polymorphisms and bone mineral density in Hungarian primary biliary cirrhosis patients.


METHODS
Seventy female patients with primary biliary cirrhosis were enrolled (mean age 57.6 years, range 37-76 years; all anti-mitochondrial antibody M2-positive; stage II-IV). One hundred and thirty-nine age-matched female subjects served as controls (mean age 55.9 years, range 43-72 years). COLIA1 and IGF-I polymorphisms were determined by polymerase chain reaction. Bone mineral density was measured by dual-energy X-ray absorptiometry in the lumbar spine and femoral neck.


RESULTS
The IGF-I was not different between primary biliary cirrhosis patients and controls. The genotype frequency of COLIA1 polymorphism was also not different between primary biliary cirrhosis patients and controls. However, the s allele was significantly less frequent in patients with primary biliary cirrhosis. Osteoporosis was detected in 22 patients. The IGF-I 192/192 genotype was associated with higher femoral-neck z-scores compared with other genotypes.


CONCLUSIONS
In contrast to previous studies, the s allele was less frequent in patients with primary biliary cirrhosis, and its presence was not associated with bone mineral density. Since IGF-I polymorphism was associated with bone mineral density, it may be hypothesised that not COLIA1 but IGF-I together with other genetic and environmental factors may be involved in the complex regulation of bone mineral density in primary biliary cirrhosis.
Lakatos
Peter Laszlo
PL
First Department of Medicine, Semmelweis University, Budapest. kislakpet@bel1.sote.hu
Bajnok
Eva
E
Tornai
Istvan
I
Folhoffer
Aniko
A
Horvath
Andrea
A
Lakatos
Peter
P
Habior
Andrzej
A
Szalay
Ferenc
F
D000328:Adult; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D024042:Collagen Type I / Q000235:genetics*; D000090602:Collagen Type I, alpha 1 Chain; D005260:Female; D005787:Gene Frequency; D016678:Genome; D006801:Humans; D006814:Hungary; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000627:therapeutic use; D008105:Liver Cirrhosis, Biliary / Q000150:complications / Q000235:genetics*; D018895:Microsatellite Repeats; D008875:Middle Aged; D010024:Osteoporosis / Q000209:etiology / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic; D018709:Statistics, Nonparametric
D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D007334:Insulin-Like Growth Factor I