染色体異常と神経学的異常

Chromosome aberrations and neurological disorders

　染色体異常は多彩な臨床像を呈する疾患群である。とくに神経症状の面からみると，精神遅滞や筋緊張低下，痙攣などがしばしば認められる。本項ではまず染色体異常の疫学に触れ，次いで染色体異常の診断について解説を行ない，具体的な染色体異常疾患について臨床細胞遺伝学の進歩と対比させながら，述べることにする。

Abstract

Various constellations of clinical features are recognized in chromosomal syndromes. In special regards to neurological findings, mental retarda-tion, muscle hypotonia and convulsion are fre-quently observed. Incidence of chromosome aber-rations varies in various populations. For example, the incidence of chromosome aberrations in first trimester spontaneous abortuses reaches to 50 per-cent. In newborn population, approximately 1 of every 160 liveborn infants has a demonstrable chromosomal abnormality.

In this section, classical chromosomal syndromes and newly established syndromes are reviewed.