HAPTOGLOBIN PHENOTYPES AND GENE-FREQUENCIES IN BIPOLAR DISORDER - AN ASSOCIATION STUDY IN FAMILY-HISTORY SUBGROUPS

Several studies have shown that major depression is accompanied by sig nificantly increased plasma levels of positive acute-phase proteins su ch as haptoglobin (Hp). A significant higher frequency of the HP1 all ele has recently been detected in patients with unipolar major depress ion. Pursuing the hypothesis that certain unipolar and bipolar disorde rs may be genetically related, this study analyzed Hp genotype and all ele frequencies in bipolar patients, taking into account their family history of major affective disorders. An increase of HP1 allele frequ ency was found in the subgroup of patients with family history of excl usively unipolar disorder (70% in patients vs. 38% in controls, chi(2) = 8.34, p = 0.004). The relative risk for the HP1 carriers in this s ubgroup was 3.8 (chi(2) = 7.29, p = 0.007). These results suggest a ge netic and etioIogical heterogeneity in the bipolar disorder.