平腦畸形(Iissencephaly)若是因為腦迴完全缺乏發育,致腦表平滑,而稱無腦迴畸形(agyria);或發育不完全致腦迴大,腦溝淺,而稱腦迴平厚(pachygyria)。本篇報告18個月女嬰,出生時沒有產傷及窒息現象,體重3250公克,外觀正常。新陳代謝疾病篩檢及染色體檢查皆無異常,家族史無特殊發現。住院時理學檢查發育正常,外觀無異常,臉部對稱無小頭現象;餵食正常無嗆時情況,沒有癲病史;但有嚴重的精神運動性異常,包括抬頭功能不好,至今仍無法翻身及坐立,下肢在站立時呈現僵硬現象。血液、尿液及血液生化換查都正常;頭部X光正常,腦部電腦斷層發現腦室大,薛氏裂較寬,腦溝較少,灰質異位,具伴有胼胝體發育不良,因而診斷為腦迴平厚。電腦斷層用於診斷平腦畸形或腦迴平厚是一種非常重要而且是非侵襲性的檢查。
Lissencephaly (agyria) is a developmental malformation characterized by an absence of cerebral convolutions. Pachygyria is a related malformation with relatively few broad gyri and shallow sulci. Our patient, an 18-month-old girl was the product of an uncomplicated full-term pregnancy and uneventful delivery to healthy patients. The infant was born weighing 3250 gm. There were neither external malformations nor particular dysmorphic features. Screening for inborn errors of metabolism was negative and chromosomal pattern was normal. On admission, physical examination revealed psychomotor delay since early infancy with slow growth. The face was symmetrical. She could suck and swallow, but had not developed head control, nor could she roll over or sit by herself. Muscle tone was high and spasticity of the limbs with left side predominance was also noted. The hemogram, urinalysis, and blood biochemistry were normal. Skull X-rays were normal. A diagnosis of pachygyria was made by CT scan of the brain. Computed tomography is reportedly an important, noninvasive, and possibly specific test. Thus, early diagnosis in life is possible for subsequent medical management of patient and genetic counseling.