A lot vs. Alot: 9 Grammatical Pitfalls
|Down syndrome (doun) or Down's Syndrome |
A congenital disorder caused by the presence of an extra 21st chromosome. People with Down syndrome have mild to moderate mental retardation, short stature, and a flattened facial profile. The syndrome is named after its discoverer, British physician John Langdon Haydon Down (1828-1896).