A congenital disorder caused by an extra chromosome 21 in some or all cells. It causes a variable number and degree of abnormalities, including retarded growth, mental retardation, a short nose, prominent epicanthic folds on the eyelids, a protruding lower lip, and other physical features having varying degrees of deviation from the normal. Called also mongolism, trisomy-21 and trisomy 21 syndrome.
A congenital abnormality in which the baby is born mentally retarded, with an average IQ of 50 - 60 and with physical deformation of the face (low set ears, sloping forehead, mongoloid eyes), and shortness of stature. Downs syndrome is caused by an extra chromosome 21 present in the G group. In a small percentage of cases it can be caused by the switching of chromosomes 14 or15 in the D group or chromosome 21 or 22. Down's syndrome occurs in about 1 in 650 births, and is more commonly associated with children of mother's over the age of 35. Incidence in children of mothers over the age of 40 can be as high as 1 in 80. Down's syndrome can be detected prenatally through amniocentesis. The mortality rate is high within the first few years. Down's syndrome is also known as mongolizm, trisomy 21 or trisomy G syndrome.
Condition associated with a chromosome abnormality, usually trisomy of chromosome 21. See Trisomy. Symptoms and findings include a small, flattened skull, short, flat-bridged nose, an abnormal fold at the inner edge of the eyes, short fingers and toes, and moderate to severe mental retardation.