Search results
Results from the WOW.Com Content Network
Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with developmental delays, mild to moderate intellectual disability , and characteristic physical features.
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 ). The effects of the extra copy varies greatly from individual to individual, depending on the extent of the extra copy, genetic background ...
Frequency. ~1 in 1,000 males [1] XYY syndrome, also known as Jacobs syndrome, is an aneuploid genetic condition in which a male has an extra Y chromosome. [1] There are usually few symptoms. [2] These may include being taller than average and an increased risk of learning disabilities.
The syndrome is named after Dutch pediatrician Cornelia Catharina de Lange, who described it in 1933. It is often termed Brachmann de Lange syndrome or Bushy syndrome and is also known as Amsterdam dwarfism. Its exact incidence is unknown, but it is estimated at 1 in 10,000 to 30,000.
Jérôme Jean Louis Marie Lejeune (13 June 1926 – 3 April 1994) was a French pediatrician and geneticist, best known for his work on the link of diseases to chromosome abnormalities, most especially the link between Down Syndrome and trisomy-21 and cri du chat syndrome, amongst several others, and for his subsequent strong opposition to the ...
XX male syndrome, also known as de la Chapelle syndrome, is a rare condition in which an individual with a 46,XX karyotype develops a male phenotype. Synonyms for XX male syndrome include 46,XX testicular difference of sex development (or 46,XX DSD)
This is a list of people with Down syndrome, a condition also known as Down's syndrome or trisomy 21. Down syndrome is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with developmental delays, characteristic physical features, and mild to moderate intellectual disability.
World Down Syndrome Day (WDSD) is marked each year on March 21, beginning in 2007. The 21st day of March (the 3rd month of the year) was selected to signify the uniqueness of the triplication ( trisomy ) of the 21st chromosome which causes Down syndrome .
Understanding the genes involved may help to target medical treatment to individuals with Down syndrome. It is estimated that chromosome 21 contains 200 to 250 genes. Recent research has identified a region of the chromosome that contains the main genes responsible for the pathogenesis of Down syndrome, located proximal to 21q22.3. The search ...
A mother's age is one of the many environmental factors that might lead to genetic abnormalities. The implications of chromosomal abnormalities depend on the specific problem, they may have quite different ramifications. Some examples are Down syndrome and Turner syndrome.