Chromosomal abnormality in a child is also associated with the maternal age. Increasing maternal age also increases the possibility of the development of chromosomal abnormality or genetic disease in a child. Women's fertility gradually decreases at the age of 30, after 35 fertility declines rapidly. Due to the advances in the fertility techniques, now women can get pregnant until she reaches the menopause, but this has got its own risk regarding the health of unborn child. Many studies have shown the correlation between the developments of chromosomal abnormality in a child is associated with the maternal pregnancy age.
Chromosomes are structures which carry the genetic material or genome of a person. In human 23 pairs of chromosome are present in every cell of the body. One set inherited from the mom and the other from the dad. 22 pairs of chromosome are autosomal, that is these chromosomes dictate the characteristics, behaviour of a person. The remaining one pair is the sex chromosomes; they determine the sex of a person. If both are X-chromosomes then the individual is female. If one is Y then the individual is male.
Chromosomal abnormalities some time are inherited from the parents, and also some random mutations may occur in the unborn foetus or children without the family history of disease. The factors which can cause such abnormalities in the chromosome include age of the mother, exposure to the radiation during pregnancy and other environmental factors.
Common Chromosomal Abnormalities related to Late Pregnancy:
A most common chromosomal abnormality which has got a strong link with the maternal age is Down syndrome. In Down syndrome, the baby has got three chromosome 21 instead of a pair. That is all the genes present in chromosome 21 are present in an extra copy in all Down syndrome patients. Most common physical features of Down syndrome are short limbs, slant eyes, small head, and abnormally-shaped ear lobes. Children with Down syndrome also suffer from mental retardation and also they will have defects in the heart.
The possibility of having a Down syndrome child increases with the increasing maternal age. The risk is minimal that is 1 in every 1500 births when the maternal age is 20, as the age increases the risk also increases. When the maternal age is 35 the risk increases to 1 in every 50 births.
Patau syndrome is very severe form of chromosomal abnormality. Trisomy or usual one set and an extra copy of chromosome number 13 causes the syndrome. But the Patau syndrome is the rarest form of syndrome.
Patau syndrome child show severe mental retardation, flexion of the fingers, polydactyly, facial clefts, defects of the neural tube, holoprosencephaly and heart defects are commonly seen. Patau syndrome is seen in 1 in every 8,000 - 12,000 births. But as the maternal age increases the possibility of having a child with this syndrome also increases.
Another chromosomal abnormality or genetic disorder associated with the maternal age is Edward's syndrome.
Increased maternal age is one of the main factors which increase the risk of having a child with chromosomal abnormality or genetic disorder. Researchers believe that as the women ages the quality of the genetic material of the egg also changes. These genetic changes in the egg increase the chances of having a child with genetic abnormality. Researches also say that there is also a link between the paternal age and the genetic syndrome.
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