noun
Down syndrome
Medical term for the chromosomal condition. In everyday conversation, ダウン症 is more common.
ダウン症候群は21番染色体のトリソミーによって起こる。
Down syndrome is caused by trisomy of chromosome 21.
ダウン症 is the more common, everyday term for Down syndrome, while ダウン症候群 is the formal medical name.
From English 'Down syndrome' (named after John Langdon Down) + 症候群 (syndrome).