Down syndrome - Symptoms and causes - Mayo Clinic
网页2018年3月8日 · Down syndrome is a genetic disorder caused when abnormal cell division results in an extra full or partial copy of chromosome 21. This extra genetic material causes the developmental changes and physical features of Down syndrome.
Down syndrome - Wikipedia
网页Down syndrome (United States) or Down's syndrome (United Kingdom and other English-speaking nations), also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. [3]
Down Syndrome | Birth Defects | CDC - Centers for Disease …
网页2024年5月16日 · Down syndrome is a genetic condition where a person is born with an extra chromosome. This can affect how their brain and body develop. People diagnosed with Down syndrome can lead healthy lives with supportive care.
About Down Syndrome - National Human Genome Research …
网页2017年6月29日 · When Down syndrome is suspected in a person, a genetic test called a chromosome analysis is performed on a blood or skin sample to look for an extra chromosome 21 (trisomy 21). Trisomy 21 means that each cell in the body has three copies of chromosome 21 instead of the usual two copies.
Down Syndrome: Symptoms & Causes - Cleveland Clinic
网页2023年1月31日 · Down syndrome is a genetic condition where a person is born with an extra copy of chromosome 21. This means that they have a total of 47 chromosomes instead of 46. This can affect how their brain and body develop. People diagnosed with Down syndrome have happy and healthy lives with supportive care.
Down Syndrome - StatPearls - NCBI Bookshelf - National Center …
网页2023年8月8日 · Down syndrome (trisomy 21) is a genetic disorder caused by the presence of all or a portion of a third chromosome 21. Patients typically present with mild to moderate intellectual disability, growth retardation, and characteristic facial features.
Trisomy 21 (Down Syndrome) - Children's Hospital of Philadelphia
网页What is Trisomy 21 (Down syndrome)? Trisomy 21 is the most common chromosomal anomaly in humans, affecting about 5,000 babies born each year and more than 350,000 people in the United States. Also known as Down syndrome, trisomy 21 is a genetic condition caused by an extra chromosome.
Genetics of Down syndrome - Wikipedia
网页Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on chromosome 21, either in whole (trisomy 21) or part (such as due to translocations).
Down Syndrome (Trisomy 21) - Down Syndrome (Trisomy 21)
网页Down syndrome is caused by an extra chromosome 21. Children with Down syndrome have delayed physical and mental development, specific head and facial features, and are often short. Before birth, Down syndrome may be suspected based on ultrasonography or tests on the mother's blood and confirmed using chorionic villus sampling and/or …
Down Syndrome (Trisomy 21) - Down Syndrome (Trisomy 21)
网页Down syndrome is an abnormality of chromosome 21 that can cause intellectual disability, microcephaly, short stature, and characteristic facies. Diagnosis is suggested by physical anomalies and abnormal development and confirmed by cytogenetic analysis. Management depends on specific manifestations and anomalies.