Association of apolipoprotein B XbaI gene polymorphism and lipid profile in northern Indian obese

BACKGROUND:

Over the last few decades, obesity, diabetes, and hypertension have become main health evils. The health problems of obesity are well-recognized. However, the fact that all obese individuals are not at the same risk of developing a disease is also recognized. The apolipoprotein B (APOB) plays a central role in lipid metabolism. So we compare the association of APOB XbaI gene polymorphism and lipid profile total in obese north Indian population.

MATERIALS AND METHODS:

A total of 132 obese (body mass index [BMI] >25 kg/m²) and 132 age matched non-obese (BMI ≤ 25 kg/m²) subjects were studied after taking detailed clinical profile. Lipid profile in serum/plasma was done using commercial kits. Genetic analysis of APOB XbaI was done using Polymerase Chain Reaction-Restriction Fragment Leanth polymorphism (PCR-RFLP).

STATISTICAL ANALYSIS:

Statistical analysis was performed by Statistical Package for the Social Sciences (SPSS) (version 11.5) software (IBM Corporation). All continuous variables were expressed as mean ± SD and tested by analysis of variance test. Comparisons of categorical variables were assessed using χ² tests or Fisher''s exact test. P < 0.05 was considered as significant.

RESULTS:

Analysis showed that obese subjects had significantly higher value of the waist-to-hip ratio, blood pressure (systolic and diastolic), and lipid profile. In APOB XbaI gene polymorphism, we did not find significant differences in genotype or allele frequencies. Moreover, none of the studied metabolic parameters (lipid profile) showed any association with the gene polymorphism.

CONCLUSIONS:

Study reveals no considerable association of APOB XbaI gene polymorphism with obesity and lipid profile in north Indians.     

Structure of the human apolipoprotein B gene

Human apolipoprotein B100 cDNA is 14 kilobases in length and encodes a 4563-amino acid precursor protein. The corresponding human gene has been isolated as a series of overlapping lambda clones and extends over 43 kilobases. The gene comprises 29 exons and 28 introns. The distribution of introns is extremely asymmetrical, most of them appearing in the 5'-terminal one-third of the gene. Although most of the exons fall within the normal size limits for mammalian genes, two are unusually long: 1906 and 7572 base pairs. The latter exon is by far the longest reported for a vertebrate gene.