The cells in our body, throughout their lives, duplicate themselves to create new tissue. The 23 pairs of chromosomes in a cell also double to 46. But sometimes the pattern of duplication is disturbed. Instead of merely duplicating a chromosome may triplicate or even break, causing various birth defects. These disorders can be passed to future generations.
Genetic counselling is a way to screening high risk populations for various diseases like families prone to cancers, thalassaemia and many genetically transferable diseases The geneticists assess the potential risk of passing on the disorder to future generations. This helps the parents to be to take informed decision about terminating a pregnancy and avoiding the trauma of having a disabled child.
Many couples are faced with difficult situations regarding the possibility of a new born being a physically disabled child or the child may be suffering from a very troublesome illness like Thalassaemia. Some couples have a child in their family already suffering from thalassaemia and the prospects of having another child with same illness are devastating. A thalassaemic child may have to undergo repeated blood transfusions. Some may need it fortnightly.
Genetics has come a long way to solve many of such problems. Tests can be conducted to find out if the unborn child carries a thalassaemia gene. Procedures have been developed by which artificially fertilised healthy embryo can be implanted in the uterus of elderly women anxious to have a healthy child. There are also methods by which genetic mapping can be done of a person to find out if he or she is carrying any faulty chromosome.
Some of the methods employed are
Polymerase Chain Reaction (PCR): Is a procedure that can reveal whether an unborn child carries a thalassaemia gene. This procedure is done mainly to detect minute abnormalities of the genes that cause diseases like thalassaemia, cystic fibrosis, haemophilia and muscular dystrophy.
Pre-implantation Genetic diagnosis (PGD): This procedure can create and select an artificially fertilised healthy embryo and implant it in the uterus, and thus ensuring that the high risk couple has a normal baby.
Karyotyping : is done to map the genetic makeup of a person to detect any faulty sex chromosome. Karyotyping is very helpful in showing up chromosomal abnormalities that cause severe physical disabilities like Tisomys – Trisomy 21 causes Down’s Syndrome, Trisomy 18 causes limb deformities and microcephaly, Trisomy 13 gives a cleft palate.