Down syndrome occurs because of the extra copy of chromosome 21, which can cause the body and brain to develop differently than a child without the syndrome.
What does trisomy mean what does trisomy 21 lead to?
A medical term for having an extra copy of a chromosome is ‘trisomy. ‘ Down syndrome is also referred to as Trisomy 21. This extra copy changes how the baby’s body and brain develop, which can cause both mental and physical challenges for the baby.
What happens if you have trisomy 21?
It is also called trisomy 21. It includes certain birth defects, learning problems, and facial features. A child with Down syndrome also may have heart defects and problems with vision and hearing. How severe or mild these problems are varies from child to child.
How does trisomy 21 affect male fertility?
Affected individuals rarely reproduce. About 15-30% of females with trisomy 21 are fertile and have up to a 50% risk of having child also affected with trisomy 21. Infertility in males has been attributed to defective spermatogenesis, but ignorance of the sexual act may be one of the contributing factors.
Does trisomy 21 affect males or females?
Overall, the two sexes are affected roughly equally. The male-to-female ratio is slightly higher (approximately 1.15:1) in newborns with Down syndrome, but this effect is restricted to neonates with free trisomy 21.
Why is trisomy bad?
Trisomy is genetic, but it isn’t often passed down from parent to child. In that way, trisomy is similar to many cancers. Both result from a random mistake. A whole range of mistakes can happen in a normal cell and cause cancer.
What are the signs of Down syndrome during pregnancy?
Some common physical signs of Down syndrome include:
- Flat face with an upward slant to the eyes.
- Short neck.
- Abnormally shaped or small ears.
- Protruding tongue.
- Small head.
- Deep crease in the palm of the hand with relatively short fingers.
- White spots in the iris of the eye.
Can a Down syndrome child look normal?
Some of the children with Mosaic Down syndrome that we know do not actually look as if they have Down syndrome – the usual physical features are not obvious. This raises some important and difficult social issues and identity issues for both parents and children, which parents have discussed with us.
Can Down syndrome be prevented?
Down syndrome can’t be prevented, but parents can take steps that may reduce the risk. The older the mother, the higher the risk of having a baby with Down syndrome. Women can reduce the risk of Down syndrome by giving birth before age 35.
What gender does Down syndrome affect most?
Down syndrome appears to be more common among boys than girls, the study indicates. The condition is also seen more frequently in Hispanic children at birth, though the number of these children appears to level off with that of white children as they age. Black children appear less likely to have Down syndrome.
Can Down syndrome males reproduce?
As it is the only autosomal trisomy compatible with postpubertal survival, the question of fertility in these patients often arises. While females with Down syndrome are reported to be fertile or subfertile, males are reported to be infertile.