Metabolic syndrome and related variables, insulin resistance, leptin levels, and PPAR-γ2 and leptin gene polymorphisms in a pedigree of subjects with bipolar disorder.

OBJECTIVE

Evidence points to a high prevalence of metabolic dysfunction in bipolar disorder (BD), but few studies have evaluated the relatives of subjects with BD. We conducted a cross-sectional study in an extended family of patients with BD type I.

METHODS

The available relatives of the same family were interviewed (DSM-IV-R) and assessed in fasting conditions for body mass index, constituent variables of the metabolic syndrome (MS), leptin levels, insulin resistance index, and single nucleotide polymorphisms (SNPs) for the leptin receptor and promoter and PPAR-γ2 genes. The frequency of MS was compared with that recorded in the local general population.

RESULTS

Ninety-three relatives of three adults with BD were evaluated (30 aged < 18 years, 63 aged > 18 years). The frequency of MS was similar to that of the general population. Significantly higher frequencies of abnormal glucose, total and low density cholesterol (LDL-c) levels (all p < 0.05), waist circumference (p = 0.057), and leptin and insulin resistance values (in adults only) were observed in the family. Adults with the QQ genotype of the leptin receptor displayed higher LDL-c levels than carriers of the R allele.

CONCLUSIONS

The associations among BD consanguinity, familial hypercholesterolemia, and leptin receptor SNPs reported herein should be replicated and extended in other pedigrees.