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Genetics may account for prevalent AMD subtype in Asians
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VIENNA, Austria — An alternative genetic pathway leading to polypoidal choroidal vasculopathy may account for the higher prevalence of this subtype of neovascular age-related macular degeneration in Asian eyes, according to recent studies.
At the Advanced Retinal Therapy meeting, Nagahisa Yoshimura, MD, said that the PCV subtype is seen in nearly 50% of Asian cases of AMD compared with less than 10% of Caucasian cases.
Nagahisa Yoshimura
“Through several studies, we found that a subgroup of PCV patients with specific morphological characteristics may fall into the category of pachychoroid neovasculopathy cases. They typically present foveal choroidal thickness of more than 200 µ in both eyes, choroidal vascular hyperpermeability (CVH) or retinal pigment epithelium abnormalities and lack of drusen. In a population of 200 Japanese PCV patients, such cases were about 20%,” Yoshimura said.
Yoshimura hypothesized that these patients with thicker choroids and vascular hyperpermeability might have a different genetic background compared with other patients with AMD.
“So far, drusen were thought to predispose to CNV, but there may be a different genetic pathway that induces thicker choroid and CNV with CVH and that is independent from the previously discovered drusen-complement system or RMS2 system. These cases might at least partly account for the higher prevalence of PCV in the Asian population. Amongst Japanese, about 20% of AMD cases might be pachychoroid neovasculopathy,” Yoshimura said.
Disclosure: Yoshimura has no relevant financial disclosures.