M. Alda et al., MN BLOOD-GROUPS AND BIPOLAR DISORDER - EVIDENCE OF GENOTYPIC ASSOCIATION AND HARDY-WEINBERG DISEQUILIBRIUM, Biological psychiatry, 44(5), 1998, pp. 361-363
Background: MN blood groups have been studied in the past as a genetic
marker of bipolar disorder (BD). Several previous studies reported ar
t association of the illness with lower frequency of blood group NN, M
ethods: We analyzed distribution of MN blood groups in a sample of 174
patients with ED, 176 with unipolar depression, 98 with schizophrenia
, and 331 healthy controls. In addition, we tested whether the inferre
d genotypes conform to Hardy-Weinberg equilibrium (HWE), Results: The
frequency of NN phenotype was significantly lower among the bipolar pa
tients than in any of the other three groups (p < .001), The genotype
frequencies in the ED group deviated significantly from those expected
under HWE (p < .01), Conclusions: These results suggest a possible lo
cus on chromosome 4 (4q28-q31.1) associated with generic susceptibilit
y to bipolar illness. (C) 1998 Society of Biological Psychiatry.