先天性外胚叶缺陷(Congenital ectoder-mal defect)亦称家族性外胚叶发育不良,外胚层发育不全,外胚层结构不良等,是一种少见的遗传性综合征。其主要临床表现有:1.先天性汗腺缺乏或异常;2.毛发(包括眉毛、睫毛),皮脂腺发育不全;3.皮肤柔软、薄细、光滑、干燥;4.指(趾)变厚或结构不良;5.牙齿缺损或发育异常;6.面容特殊,前额突出,鼻梁下 Congenital ectodermal defect (Congenital ectoder-mal defect), also known as familial ectodermal dysplasia, ectodermal hypoplasia, ectodermal dysplasia, is a rare hereditary syndrome. The main clinical manifestations are: 1 congenital absence or abnormal sweat glands; 2 hair (including eyebrows, eyelashes), sebaceous glands hypoplasia; 3 skin soft, thin, smooth and dry; Poor structure; 5. Teeth defects or dysplasia; 6. Special face, prominent forehead, nose