What is autosomal recessive inheritance

How Tay-Sachs is passed on when both parents are carriers

Tay-Sachs is classed as an autosomal recessive disease – this relates to how the disease is passed on genetically.

To understand what autosomal recessive inheritance means you first need to break down the words:

  • Autosomal – this means the disease affects both males and females equally
  • Recessive – this means both parents must be a carrier for a child to be at risk although the parents themselves (the carriers) are not affected by the disease
  • Inheritance – this means the process of genetic transmission of characteristics (in this case the gene which causes Tay-Sachs) from parents to offspring.

It is possible to then understand that autosomal recessive inheritance describes the process of how the gene which causes Tay-Sachs passes from parent to child and why the parents as carriers are not affected by the disease but together they are at risk of having children affected by Tay-Sachs.

To further understand why a child is born with Tay-Sachs we need to look at how the gene is passed on and what the actual chances of it happening are.

How Tay-Sachs is passed on when both parents are carriers

Both parents carriers

High-risk couples, which are described as a man and the woman who are carriers of the same genetic condition, have a 25% chance with each pregnancy of conceiving a child with that condition.

There is a 50% chance of producing a child who is a carrier like the parents and a 25% chance that the child will be neither a carrier nor affected with the disease.

The image on right details each different genetic scenario where both parents are carriers.

How Tay-Sachs is passed on when one parent is a carrier

 

 

 

One parents a carrier

If only one parent is a carrier of the gene which causes Tay-Sachs then there is no chance of producing a baby with a recessive disease.

However, there is a 50% chance in each pregnancy that the child themselves will be a carrier who can then pass the gene onto their children in the future.

The image on the right details each different scenario where only one parent is a carrier.

The information has kindly been produced in conjunction with the NTSAD.

Daniel is the father of a little girl called Amelie who was diagnosed with Tay-Sachs in March 2011 when she was 15 months old. After slowly coming to terms with what the future held, Daniel, his wife Patricia and their friends started THE CATS FOUNDATION to raise awareness of the disease and to provide fund raising opportunities so that a potential treatment can be found.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

*