Genetic variation at CHRNA5-CHRNA3-CHRNB4 interacts with smoking status to influence body mass index.

Background: Cigarette smoking is associated with lower body mass index (BMI), and a commonly cited reason for unwillingness to quit smoking is a concern about weight gain. Common variation in the CHRNA5-CHRNA3-CHRNB4 gene region (chromosome 15q25) is robustly associated with smoking quantity in smokers, but its association with BMI is unknown. We hypothesized that genotype would accurately reflect smoking exposure and that, if smoking were causally related to weight, it would be associated with BMI in smokers, but not in never smokers.

High-resolution HLA genotyping and severe cutaneous adverse reactions in lamotrigine-treated patients.

Background: Severe cutaneous adverse reactions (SCARs) are associated with over 200 medicines including lamotrigine, an antiepileptic drug. Previous studies have suggested the involvement of immune mechanisms in the development of drug-induced SCARs.

Methods: High-resolution HLA genotyping was performed for 65 patients of European ancestry treated with lamotrigine (22 cases with lamotrigine-induced SCARs and 43 controls on lamotrigine without SCAR-related symptoms).

Haplotypes of the beta2-adrenergic receptor gene are associated with essential hypertension in a Singaporean Chinese population.

Objective: To investigate the relation between the gene encoding the beta2-adrenergic receptor (B2AR) and essential hypertension in a Singaporean Chinese cohort.

Methods: Three single nucleotide polymorphisms (SNPs) were genotyped in 190 cases and 323 controls, and eight haplotypes were determined and tested for association using the likelihood test statistic.

Results: We observed a significant difference in haplotype frequency distributions between the cases and the controls (P <0.