04/04/2026
Symptoms and Characteristics of
Down Syndrome 。。。唐氏综合征
唐氏症、21-三体综合征 (Trisomy 21 Syndrome），是由于人体细胞染色体组存在额外的第三条21号染色体（正常为两条）或其一部分而引起的一种先天性染色体异常性疾病，属于一种三体综合征。
Down syndrome is a genetic condition caused by an extra copy of Chromosome 21 (Trisomy 21), leading to mild-to-moderate intellectual disability, characteristic physical traits (e.g., flat facial profile, almond-shaped eyes), and potential health issues like heart defects. It affects development by causing delays in motor skills, speech, and cognitive function, though early intervention significantly improves outcomes.
Key Aspects of Down Syndrome :
1) Causes :
It results from random errors in cell division (Trisomy 21, translocation, or mosaicism).
2) Risk Factors :
The primary risk factor is advanced maternal age, particularly over 35, although it can occur at any age.
3) Physical Symptoms :
Common features include poor muscle tone (hypotonia), a short neck, small ears, hands, and feet, and a single crease across the palm.
4) Developmental Effects :
Individuals often experience delayed cognitive development, slower speech and language development, and impulsive behavior.
5) Health Complications :
Associated risks include congenital heart defects, thyroid issues, hearing/vision loss, and increased risk of Alzheimer’s disease.
While challenges exist, individuals with Down syndrome often lead active, fulfilling lives with appropriate support.
