APOLIPOPROTEIN-E GENE POLYMORPHISM IN EARLY AND LATE-ONSET BIPOLAR PATIENTS

To explore the involvement of apolipoprotein E gene (APO E) in major d epression, we studied the APO E gene polymorphism in a sample of 156 u nrelated bipolar patients and 91 healthy volunteers. This population w as stratified for age at onset of the affective disorder (onset before 18 years, after 45 years and between 18 and 45 years). Early onset bi polar patients with psychotic symptoms exhibited a significant increas e of epsilon 4 allele frequency (28.9%) compared to either other bipol ar patients (13.1%, chi(2) = 6.52, df = 1, P < 0.02) Or controls (12.1 %, chi(2) = 7.01, df = 1, P < 0.01). The association between epsilon 4 and early onset bipolar disorder (BPD) with psychotic symptoms sugges ts that APO E gene is a risk factor for a subgroup of BPD, or influenc es the phenotypic expression (i.e. psychotic symptoms or age at onset) of manic depressive illness. (C) 1997 Elsevier Science ireland Ltd.