What are Down syndrome, Trisomy 18 and Trisomy 13?
Down syndrome occurs when there is an extra copy of chromosome 21. Individuals with Down syndrome have mental retardation and often physical anomalies, like heart defects. Trisomy 18 occurs when there is an extra chromosome 18; Trisomy 13 when there is an extra chromosome 13. Both disorders can cause mental retardation and other birth defects. While Trisomy 18 and Trisomy 13 are more severe than Down syndrome, they are less common. The above disorders make up approximately half of the chromosomal abnormalities seen at live birth. Early Screen may detect some, but not all, of the remaining chromosomal abnormalities.
Related Questions
- Are women who screen positive for Down syndrome, trisomy 18, or ONTDs in a previous pregnancy eligible for an amniocentesis in their current pregnancy?
- Do the results of prenatal screening provide information other than risk for Down syndrome, trisomy 18 and open neural tube defects?
- Do the results of serum screening provide information other than risk for Down syndrome, trisomy 18 and open neural tube defects?
