What is Down Syndrome?

the down syndrome appears when a haploid cell has 23 chromosomes!

Down syndrome or trisomy 21 (also Down's syndrome) is a genetic disorder caused by the presence of all or part of an extra 21st chromosome. It is named after John Langdon Down, the British doctor who first described it in 1866. The condition is characterized by a combination of major and minor differences in body structure. Often Down syndrome is associated with some impairment of cognitive ability and physical growth as well as facial appearance. Down syndrome is usually identified at birth.
Individuals with Down syndrome can have a lower than average cognitive ability, often ranging from mild to moderate mental retardation. Developmental disabilities often manifest as a tendency toward concrete thinking or naïveté. A small number have severe to profound mental retardation. The incidence of Down syndrome is estimated at 1 per 800 to 1 per 1,000 births.
Many of the common physical features of Down syndrome also appear in people with a standard set of chromosomes. They include a single transverse palmar crease (a single instead of a double crease across one or both palms), an almond shape to the eyes caused by an epicanthic fold of the eyelid, shorter limbs, and protruding tongue. Health concerns for individuals with Down syndrome include a higher risk for congenital heart defects, gastroesophageal reflux disease, recurrent ear infections, obstructive sleep apnea, and thyroid dysfunctions.
Early childhood intervention, screening for common problems, medical treatment where indicated, a conducive family environment, and vocational training can improve the overall development of children with Down syndrome. Although some of the physical genetic limitations of Down syndrome cannot be overcome, education and proper care will improve quality of life

i don't know more about that syndrom..sorry. i cannot share information for you..:(