Can trisomy 18 happen twice?
The recurrence risk for a family with a child with full trisomy 18 is usually stated as 1% (1 in 100). Therefore, the vast majority of parents with an affected fetus or child go on to have normal children.
Does trisomy 18 run in families?
Trisomy 18 does not typically run in families. Occasionally, one parent may have a chromosome rearrangement that increases the chance of having children with chromosome differences.
What are the chances of having a baby with trisomy 18?
Trisomy 18 occurs at a rate of 1 in 2000-6000 live births. It is somewhat more common as the mother ages but can occur randomly to parents of any age. The majority of babies affected are girls. There is no known cause of Trisomy 18.
Can trisomy happen twice?
Recurrence of trisomy in the same couple could occur for several reasons: (1) chance alone, due to the maternal age–associated risk, (2) parental gonadal mosaicism for trisomy, or (3) factors associated with an increased risk of meiotic error.
Is trisomy 18 ever misdiagnosed?
More than 90% of women with this result are carrying a baby with trisomy 18. However, there is a small chance for a “false positive” result. A false positive result is when the test shows a high risk for trisomy 18, but the baby does not have this condition.