僧帽弁逸脱症における経過観察・家系内検索の臨床的意義—僧帽弁閉鎖不全，突然死，胸郭変形を認めた一家系の呈示と考察

Clinical significance of follow-up observation and family survey in patients with mitral valve prolapse. Special reference to mitral regurgitation, sudden death and thoracic skeletal abnormalities

　1961年，Reidは収縮期クリック・収縮後期雑音（latesystolic murmur, LSM）が僧帽弁腱索の異常により引き起こされ^1），僧帽弁閉鎖不全（mitral regurgitation，MR）を伴う可能性を提唱し，Barlowらは1963年，左室造影により直接僧帽弁逆流を証明した^2）。ここに今日の膨大な僧帽弁逸脱（mitral valve prolapse,MVP）に関する研究の素材となる概念の萌芽があったと思われる。MVPは今やMRの一因として重要で，心エコー法の普及とともに急速に臨床的研究が進歩した反面，一部に診断上の混乱をまねいている。

　今回我々は，漏斗胸とLSMを伴うMVPを合併した16歳女性例を経験し，その家系内検索により発端者よりも重症の腱索断裂（ruptured chordae tendineae，RCT）によるMR例，突然死例，胸郭変形例をそれぞれ見出したので，症例を呈示し，これらの関連と意義について文献的考察を加えて報告する。

Mitral valve prolapse (MVP) is generally con-sidered to be benign, and is not associated with serious cardiac complications in number of cases. However, once complicated with thoracic skeletal abnormalities (TSA), the MVP syndrome has been found to have serious cardiac complications such as progressive mitral regurgitation (MR), infective endocarditis, and unexpected sudden death. Several studies have demonstrated a familial occurrence of MVP, and have suggested that the inheritable trait is of the autosomal dominant type. We experienced a 16-year-old girl (propositus) who have pectus excavatum and associated with MVP with MR. We, then, investigated the family survey, and found such serious cases as severe MR, sudden death and TSA. The importance of follow-up observation and family survey in patients with MVP with MR and/or TSA were emphasized.