Mosaicism
There is an error in the cell division after the fertilised egg splits into two cells....
In mosaicism there is an extra chromosome in some cells but other cells have normal chromosomes. The cells with 45 chromosomes die. Some children may be profoundly handicapped, but many are much lesser affected, and several SOFT children with mosaicism have entered mainstream education.
Children with mosaicism may not be diagnosed at birth, and various medical problems can eventually lead to blood tests and a diagnosis. Read Children with a related disorder.
