Trisomy 21

Down Syndrome

Trisomy 21 is a type of Down's Syndrome.

When a child has Trisomy 21, it means that the child has a genetic disorder because of "the presence of all or part of chromosome 21." (wikipedia). When the child gets older, it will have noticeable characteristics that will show the disease, such as low-set ears or eyelid creases. Children with this disease will have stunted growth and a learning disability. 1.4 children out of 1000 will have this disease in the US.

Other Facts

Cancer in DS children: Kids with DS or Trisomy 21 are less likely to get certain types of cancer, but more likely to get leukemia and testicular cancer.

Heart: 50% of DS children will have congenital heart disease.

Mind: Most kids will have a 30-70 IQ, but some may experience moderate DS, which will result in an IQ of 10-30. If the child lives to be in his or her 40's or 50's, they will most likely experience Alzheimer's disease.

Fertility: Most men with DS have a low sperm count, and woman have many miscarriages, pre-mature births or have difficulty with labor.

Senses: About 37-78% of DS/Trisomy 21 children experience hearing and sight problems.

Explained further.

Basically what happens is that during Anaphase 2, the sister chromatids of chromosome 21 do not separate, leaving one chromatin by itself and chromosome 21 still paired together.

Gracie Whatley // Holliman 2A