children s health issues
Trisomy 18
Introduction
Trisomy 18 is a chromosomal disorder caused by an extra chromosome 18 that results in intellectual disability and physical abnormalities. Trisomy 18 caused by an extra chromosome 18. Infants are typically small and have many physical abnormalities and problems with internal organs. Tests can be done before or after birth to confirm the diagnosis. There is no cure for trisomy 18. (See also Overview of Chromosome and Gene Disorders .) Chromosomes are structures within cells that contain An extra chromosome, making three of a kind (instead of the normal two), is called trisomy. Children who have trisomy 18 have a third chromosome 18. Trisomy 18 occurs in about 4 out of 10,000 pregnancies. The extra chromosome almost always comes from the mother. Mothers who are over age 35 are at increased risk of having a child with trisomy 18. There are more girls than boys with trisomy 18. 