To study the genotypes, allelic frequencies, and polymorphisms of apolipoprotein E (Apo E) in unrelated Japanese patients with polypoidal choroidal vasculopathy (PCV) or exudative age- re- lated macular degeneration (AMD) and control subjects without macular degeneration. Cross- sect- ional study. Blood samples from 225 subjects older than 50 years were used. The 225 subjects included 58 patients with PCV, 85 with AMD, and 82 without macular degeneration. Coding exons of the Apo E gene were amplified by polymerase chain reaction, and the DNA sequences were determined by direct sequencing with an automated sequencer. Apo E 3/3 was the most frequent genotype with a prevalence of 79.3% in PCV patients, 76.5% in AMD patients, and 67.1% in the control subjects. However, the differences in the percentages were not statistically significant among the three groups. The most frequently found allele in the three groups was 3. Patients with PCV and AMD were less likely to have 2 and 4 than the control subjects, but the differences were not statistically significant. Five minor Apo E single nucleotide polymorphisms, including 5 and 7, were found. Japanese patients with PCV and AMD were less likely to have 2 and 4 polymorphisms, but the differences from the normals were not statistically significant for the Apo E genotypes and allelic frequencies. To study the genotypes, allelic frequencies, and polymorphisms of apolipoprotein E (Apo E) in unrelated Japanese patients with polypoidal choroidal vasculopathy (PCV) or exudative age-re- lated macular degeneration (AMD) and control subjects without macular degeneration. Cross-sect The 225 subjects included 58 patients with PCV, 85 with AMD, and 82 without macular degeneration. Coding exons of the Apo E genes were amplified by polymerase chain reaction, and the DNA sequences were determined by direct sequencing with an automated sequencer. Apo E 3/3 was the most frequent genotype with a prevalence of 79.3% in PCV patients, 76.5% in AMD patients, and 67.1% in the control subjects. However, the differences in the percentages were not statistically significant among the three groups. 3. most with found allele in the three groups was 3. patients with PCV and AMD were less likely to have 2 and 4 than the co naugh subjects, but the differences were not statistically significant. Five minor Apo E single nucleotide polymorphisms, including 5 and 7, were found. Japanese patients with PCV and AMD were less likely to have 2 and 4 polymorphisms, but the differences from the normals were not statistically significant for the Apo E genotypes and allelic frequencies