The child being referred for Genetic Testing because the gene is an essential part of hearing loss testing process. It is performed to determine the causes of hearing loss due to genetic or non-genetic factors.
The children inherit features from patients such as hair color or eye color, sometimes hearing loss also. Commonly people have 23 pairs of chromosomes – microscopic structures that contain genes – in each of their cells. In every pair of chromosomes, one is inherited from the mother and the other is inherited from the father.
40% of childhood hearing loss is genetic. There are multiple genetic causes for hearing loss. The number of causes for hearing loss is continuously changing.
In some cases there is a change occurs in a particular gene that produces the different characteristic, for example, hearing loss. The changes occurred in a gene is a ‘fault’ or ‘mutation’.
Reasons for a child being referred for Genetic Testing:
Family history: If one or more members of the family are suffering from some of the diseases or early death in the family happens. The children belong to these kinds of families are referred for the genetic test.
Delayed growth and development: Sometimes the parents have a concern that there is a delay in the growth of their child. Further, these children refer to the genetic test.
Reproductive issues: The women whose ultrasound indicates that she can have complications in their pregnancy. The couple who are first cousins or have some blood relations. Their children are more likely to imitate for any genetic disorder. So in order to get rid of diseases, they should undergo a genetic test.
Researchers basically categorized hearing loss in two types Non-Syndromic and Syndromic hearing loss
Non-Syndromic: Non-syndromic hearing loss is that which does not produce any other symptoms.
Syndromic: Syndromic hearing loss is that which produce other symptoms or medical conditions
There are two genetic factors which are responsible for hearing loss:
Genes can work in different ways. Sometimes a child only needs to inherit one gene, from either their mother or their father (dominant inheritance), to have that particular characteristic.
Sometimes the child would need to have the same gene passed on from both parents in order to have a condition (recessive inheritance).
X-linked or Sex-linked:
This hearing occurs when the changed gene depends on the X chromosome. AS we know the female has 2 X chromosome and male has 1 X chromosome. The female chromosome rarely shows the effects on a changed gene on the X chromosome while the male X chromosome shows the effect on a changed gene.
Mitochondria Gene Effect
Genes are stored in the mitochondria. Mitochondria are the powerhouse of the cell. The mistake in mitochondrial genes affects the functioning of the body part such as ears, eyes, kidneys, muscle, and heart. These type of changes result in hearing loss.
Genes pass from one generation to another generation. So as mitochondrial genes are passes. Changed mitochondrial genes determine the severity of loss.