双生児にみられた網膜血管走行異常

Congenital disorder of retinal vessels in a pair of twins

要約　目的：双生児に発見された網膜血管の報告。症例：17歳男児が眼底の血管異常で紹介され受診した。未熟児であったが詳細は不明である。所見：矯正視力は左右とも1.5であり，左眼に乳頭から発する血管が蛇行・怒張し，網膜のつた状血管腫（racemose angioma）と診断した。蛍光眼底造影で血管の透過性亢進と閉塞はなかった。一卵性双生児の第2子であり，第1子を精査した。視力は正常で，右眼網膜に血管の蛇行と怒張が軽度にあった。蛍光眼底造影で循環動態に異常はなかった。結論：つた状血管腫が双生児の第2子の左眼にあり，軽度の網膜血管走行異常が第1子の右眼にあり，鏡像を呈した。網膜血管の走行異常の発生原因が先天性で，その重篤度に後天性要因の関与があると推定される。

Abstract.　Purpose：To report a pair of twins who manifested congenital disorder of retinal vessels. Case：A 17-year-old male was referred for fundus anomaly. He had been born premature. Findings：Corrected visual acuity was 1.5 in either eye. The left eye showed engorged and tortuous vessels originating from and entering the optic disc. The finding was compatible with the diagnosis of racemose angioma. Fluorescein angiography showed no vasoocclusion or hyperpermeability. His twin brother showed normal visual acuity and slightly engorged and tortuous retinal vessels in the right eye. Fluorescein angiography showed normal findings. Conclusion：Retinal vascular anomaly was present in the left eye of the first patient and in the right eye in his twin brother,showing a mirror image. The findings suggest that the retinal vascular disorder is congenital in nature,while the degree and laterality is determined by acquired factors in the present cases.