Monozygotic twins with polypoidal choroidal vasuculopathy

Abstract

Purpose: To present the first findings in the set of monozygotic twins with polypoidal choroidopathy (PCV).

Methods: Sixty two-year old monozygotic twin sisters were studied. The concordances and discordances of the clinical features of the twins were determined. Genomic DNA was extracted and genotyped for three established PCV risk-associated single nucleotide polymorphisms, viz CFH I62V, CFH Y402H, and ARMS A69S.

Results: Both patients had hemorrhagic pigment epithelial detachments with orange lesions beneath the retinal pigment epithelium. Indocyanine green angiography showed pathognomonic choroidal vascular networks with polypoidal structures uniocularly in one twin and binocularly in the other twin. Both twins were treated with photodynamic therapy, retinal photocoagulation, and anti-vascular endothelial growth factor therapy, but both showed limited response to all the treatments, with recurrent exudative lesions with enlarged vascular network, and poor visual outcome. Genetic analyses showed that both sisters had homozygous risk alleles for ARMS2 A69S, and one risk allele each of CFH I62V and CFH Y402H.

Conclusions: We present the first findings in a set of monozygotic twins with typical PCV under long-term observation. The concordances in disease progression and response to treatment between the twins indicate that these genetic factors most likely played important roles in determining the clinical manifestations.

Keywords: ARMS2; CFH; PCV; monozygotic twins; polypoidal choroidal vasculopathy.

Figure 1

Case 1. Findings in a 62-year-old monozygotic twin with polypoidal choroidal vasculopathy in her right eye. Notes: A) Fundus photograph of right eye shows a hemorrhagic pigment epithelial detachment (PED) associated with an orange lesion beneath the retinal pigment epithelium (RPE) (arrows). B) Fluorescein angiogram shows dye pooling beneath the RPE. C) early phase indocyanine green angiogram (ICGA) showing a network of vessels and polypoidal structures. D) Late phase ICGA showing intense dye leakage from the polypoidal lesions. E) Three months after photodynamic therapy, the PED cannot be seen. F) ICGA showing closure of the polypoidal lesions.

Figure 2

Case 1. Three years and five months after the initial photodynamic therapy (PDT). Notes: A) Hemorrhagic pigment epithelial detachment (PED) and subretinal hemorrhage have recurred. B) Fluorescein angiogram shows pooling of dye beneath the PED and leakage of dye in the macular region. C) Indocyanine green angiogram (ICGA) delineates the polypoidal lesions and abnormal choroidal vessels that have extended from the treated site (arrows). D) Late phase of ICGA: extensive dye leakage from the polypoidal lesions and diffuse staining involving the macula. E) After photocoagulation applied to the polypoidal lesions and PDT combined with an intravitreal injection of bevacizumab: the exudative changes have subsided, leaving a subretinal fibrovascular tissue. F) Dye leakage from the fibrovascular tissue is still present.

Figure 3

Case 2. Twin sister of Case 1 with polypoidal choroidal vasculopathy in both eyes. Notes: A, B) Fundus photographs of right eye before (A) and after (B) laser photocoagulation at the age of 57 years. C) Photograph of left fundus showing an orange lesion at the margin of a hemorrhagic PED (arrows). D) Fluorescein angiogram showing leakage of dye beneath the PED. E, F) Indocyanine green angiogram (ICGA) of right eye showing polypoidal lesions at the margin of the PED (E) with late dye leakage (F).

Figure 4

Case 2. Three years after the direct irradiation. Notes: A, B) Fundus photograph (A) showing the recurrence of hemorrhagic PEDs which can be seen as leakage of fluorescein in the fluorescein angiogram (B). C) Indocyanine green angiogram showing newly-developed polypoidal structures and network vessels. D) After PDT: the exudative changes have subsided. E, F) Fundus photograph (E) seven months after PDT, showing the massive subretinal hemorrhage that has developed, with further extension of the polypoidal lesions and network vessels (F).