Carrier Screening

What is carrier screening?

It is a proven fact that most individuals are carriers for several genetic diseases even despite possessing no history of those particular diseases in their families. So, as long as these disorders don’t come in the way of people while performing their day-to-day activities and getting on with their lives, these minor ‘conditions’ can be ignored.

However, what is important to find out is whether you or your (future) partner is a carrier for the same genetic disease. In which case, the chances of conceiving a child who has a genetic condition go up significantly. Hence, it is imperative to learn whether you are indeed a carrier for a genetic disease and if so, which one before you decide to choose a partner. There are different ways in which genetic diseases are inherited. For example, ways like Autosomal Recessive and X-linked. For a person, the chances of passing on a genetic condition to his/her child depend on mainly the carrier status, the carrier status of your partner as well as the mode of inheritance for each specific disease.

Autosomal Recessive

It’s during the autosomal recessive pattern most of the conditions included in Carrier Screening are inherited. This renders both the male and female parent to be equally responsible for the future generation(s) getting affected by the disease. A person who is an autosomal recessive disease carrier has the possibility of inheriting one disease-causing copy of the gene from one parent and a healthy copy from the other. If both the parents are carriers for the same autosomal recessive disease, the chance of passing on a disease-causing copy to their offspring amounts to 25%.

X-Linked Inheritance

X-linked conditions are more often seen in males than in females exclusively passed on from mother to the child. The reason for X-linked diseases are mutations found on the X chromosome.

The reason males are greatly affected as compared to females is that males have only one X chromosome (XY), as opposed to 2 for females (XX). Hence, there is no another X chromosome to offer compensation for the affected traits in the males. For an X-linked condition to affect a male, they must receive only one disease-causing copy. The couple’s chances of bearing a healthy child get reduced to 50% if the female partner is a carrier of an X-linked genetic disorder.