口腔顎顔面の発達成長とその異常

Current treatments for oral and maxillo-facial diseases. Growth of maxillo-facial region and related anomalies.

　口腔顎顔面は形態が多様で複雑なため，発達成長の障害に伴い様々な異常が起こりうる。遺伝性疾患のうち，口腔顎顔面になんらかの異常を発症する疾患は７割に及ぶと言われている。上顎の形成異常である唇顎口蓋裂は一般集団の0.2％と，数ある外表奇形の中で最も高頻度に発症する。下顎の異常に関しては，下顎骨の矮小化した遺伝性疾患のTreacher Collins症候群やRobin sequenceは出生直後から気道閉塞に伴う呼吸困難に陥る例がある。一方，軟骨形成の障害や不全を主徴とする四肢短縮型小人症のAchondroplasiaでは，興味深いことに下顎頭軟骨の伸長が阻害されず，骨格性下顎前突を呈するものが多い。本稿では，口腔顎顔面の特異な発達成長により特徴的な表現型を呈する種々の遺伝性・先天性疾患の特徴と発症に関する機構について概説する。

　Since maxillo-facial region is quite complex, growth and developmental defect cause various anomalies. It is known that 70％ of whole genetic disorders have any symptom or abnormal condition in maxilla-facial region. Cleft lip and/or palate is the most popular congenital anomaly and is seen in 0.2％ of general population. Cases with Treacher Collins syndrome and Robin sequence are with respiratory problem due to the small mandible or mandibular retrusion. Achondroplasia is a genetic disease with short-limbed dwarfism due to abnormal proliferation or differentiation of chondrocytes. Interestingly, in this disease, growth of condylar cartilage is not impaired and causes mandibular prognathism. In this review, various diseases caused by the abnormality in growth and development of maxilla-facial region are discussed.