Down syndrome - Symptoms and causes - Mayo Clinic
2024年11月12日 · Down syndrome is a genetic condition caused when an unusual cell division results in an extra full or partial copy of chromosome 21. This extra genetic material causes …
Down syndrome - Wikipedia
Down syndrome or Down's syndrome, [12] 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] It is usually associated with …
Down Syndrome: Symptoms & Causes - Cleveland Clinic
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 …
Down Syndrome - StatPearls - NCBI Bookshelf - National Center …
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 …
About Down Syndrome - National Human Genome Research …
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 …
Down Syndrome | Birth Defects | CDC - Centers for Disease …
2024年12月26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 …
Understanding the Three Different Types of Down Syndrome
2024年4月19日 · Down syndrome is a genetic condition found in about one in 700 babies born in the U.S. A person is diagnosed when an extra chromosome is detected in their cells. The test …
Genetics of Down syndrome - Wikipedia
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 …
Trisomy 21 (Down Syndrome) - Children's Hospital of Philadelphia
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 …
Down Syndrome (Trisomy 21) - Down Syndrome (Trisomy 21)
Down syndrome is an abnormality of chromosome 21 that can cause intellectual disability, microcephaly, short stature, and characteristic facies. Diagnosis is suggested by physical …