Chronological Observations of Iris Flocculi in a Japanese Family with Thoracic Aortic Aneurysm and Dissections

摘要

Iris flocculi, a type of hereditary iris pigment epithelial cyst, have been reported in association with smooth muscle α-2 actin (ACTA2) gene as the causative gene of familial thoracic aortic aneurysm and dissections (FTAAD). The purpose of the report was to examine morphological changes in the shape of flocculi and iris features over time by comparing infants to adults with FTAAD combined with iris flocculi. A Japanese family with FTAAD and bilateral iris flocculi and the Arg149Cys gene mutation was included. A slit-lamp photograph and anterior segment optical coherence tomography (AS-OCT) were used to evaluate the structure and location of iris flocculi. AS-OCT was also used to measure the internal shape and iris thickness of the dilated pupil muscle. A morphological change in the cyst was confirmed to be existent in the youngest cases. Pigment discoloration and iris atrophy of the iris body were observed in all cases. Besides, a decrease in iris thickness was observed with AS-OCT measurement. Changes across generations in iris flocculi occurred in a Japanese family with TAAD. ACTA2 gene abnormalities may cause iris atrophy and decrease thickness in addition to iris flocculi in early life. The prognosis is poor when FTAAD is combined with iris flocculi, and prevention of cardiovascular disease is necessary based on earlier findings of its emergence.