Apolipoprotein E epsilon 4 allele and Japanese late-onset depressive disorders

Several studies have suggested that late-onset depressive disorder (LOD) and the apolipoprotein E (Apo E) epsilon 4 allele are associated with dementia, respectively. The Apo E polymorphism is significantly heterogeneous among races. We hypothesized that the Apo E epsilon 4 allele frequency is elevated in Japanese LOD.

The Apo E genotype was studied in 134 patients (male, 53; female, 81) with early-/late-onset depressive disorder and 105 healthy normal controls (male, 41; female, 64). The patients were subdivided into those with early onset and late onset using 45 and 50 years as the cutoff ages. All the subjects were Japanese.

There was statistically no difference between normal control subjects and patients with depressive disorders in Apo E genotype or allele frequency. There was statistically no difference in the age of onset of depressive disorders according to the Apo E genotype. There was no relation between the age of onset of depressive disorder and the number of epsilon 4 alleles the patient had. There was also no association between early-/late-onset depressive disorder and the Apo E genotype or allele frequency.

Our results suggest that there is no association between the Apo E epsilon 4 allele and Japanese LOD.