Genes and Genetic Testing
How genes work
Genes pass on instructions for the growth and development of every cell in your body and are packaged in bundles called chromosomes. In humans, each cell in the body contains 23 pairs of chromosomes – 46 in total.
You inherit one of each pair of chromosomes from your mother and one from your father.
Genes determine your blood group, eye and hair colour and also your risk of inheriting certain medical conditions as well.
The pattern of inheritance is varied and the condition which is inherited depends on what instructions the changed gene was supposed to give the body. Different changes in genes cause different conditions.
The basic patterns of inheritance are called autosomal dominant, autosomal recessive, and X-linked inheritance.
Dominant Inheritance - One parent carries a normal copy of a gene and a changed copy which overpowers its normal counterpart , so that aprent is affected with the condition. When the affected parent has a child with an unaffected and non-carrier partner , the child may be affected or not affected, but they are not carriers. Children have a 50% risk for disease in this case.
Recessive Inheritance - Both parents carry a normal copy of a gene and a changed copy . The parents, although carriers, are unaffected by the changed gene. Their children may be affected if they inherit the changed gene from each parent, otherwise they will not be affected, but they may be carriers. Children have a 25% risk for disease, or less in this case.
The UK Genetic Testing Network (UKGTN) provides a database yopu can search to find a testig centre near you