HAPTOGLOBIN PHENOTYPES AND GENE-FREQUENCIES IN UNIPOLAR MAJOR DEPRESSION

Objective: Studies from the authors' laboratory have shown that major depression is accompanied by significantly increased plasma concentrat ions of positive acute-phase proteins such as haptoglobin. Haptoglobin is characterized by a molecular variation with three known phenotypes (Hp 1-1, Hp 2-1, and Hp 2-2. This study investigated haptoglobin plas ma levels and phenotype and gene frequencies in unipolar major depress ion. Method: Haptoglobin plasma levels of 22 healthy volunteers, 32 pa tients with minor depression, and 72 patients with major depression we re determined by means of a laser nephelometric method. Haptoglobin ph enotyping of these 126 subjects and 200 healthy blood donors was also carried out. Results: The patients with major depression exhibited sig nificantly higher haptoglobin plasma levels than the healthy compariso n subjects and the patients with minor depression. Subjects with the h aptoglobin phenotype Hp 2-2 had significantly lower haptoglobin levels than the phenotype Hp 1-1 and Hp 2-1 carriers. The frequencies of hap toglobin phenotypes Hp 2-1 (61.1%) and Hp 2-2 (20.8%) in the patients with major depression were significantly higher and lower, respectivel y, than the frequencies in the normal population (i.e., the blood dono rs: 48.0% and 37.0%, respectively). The frequency of the Hp-1 gene was significantly greater in the patients with major depression (48.6%) t han in the normal population (39.0%). Conclusions: Major depression is characterized by a hyperhaptoglobinemia that is largely independent o f haptoglobin phenotypes. This altered distribution of haptoglobin phe notypes and genes suggests that genetic variation on chromosome 16 may be associated with that illness.