Friday, May 6, 2016
Inherited Disorders and Birth Defects
My husband and I are trying to have a baby and I`m a little concerned because I have a first cousin who has been diagnosed with fredricks ataxia. I`ve read about the disorder and understand that both parents have an abnormal gene that causes this disorder. My cousin`s dad is my dad`s brother - no other family members on this side have this disease - do I need to worry about possibly being a carrier of this??
Friedreich ataxia (FA) is a slowly progressive ataxia (a loss of balance and problems coordinating movement of legs and walking) that usually starts in the mid teens and usually before the age of 25 years. People with FA usually have absent reflexes in the legs, dysarthria (trouble swallowing or problems with speech), a loss of sensation in the lower legs and muscle weakness. People with FA can also have scoliosis (curvature of the spine), pes cavus (the breast bone sunken in), heart problems and glucose intolerance, or diabetes.
It is caused by a mutation (change) in a gene that is on chromosome 9. It is inherited in an autosomal recessive manner – that is both parents are carriers for the gene and have a 25% chance of both passing the mutated gene on at the same time and having an affected child.
In order for you to have a child with FA, both you and your husband must be carriers for the gene that causes FA. Because you have a first cousin who has the disease, you would have a 25% chance to be a carrier. If your husband does not have any affected relatives - his chance to be a carrier is the general population risk for this disease - about 1 in 90 - according to the FA Research Alliance. Then the chance that BOTH of you would pass the gene on at the same time is 25%. If you multiply these 3 numbers together, the chance that you and your husband will have a baby affected with FA is about 1 in 1400.
This is an excellent question to discuss with a genetic counselor or geneticist so that all of the issues can be discussed. You can locate a genetics center near you at the National Society of Genetic Counselors’ Resource Center below. Also, there is very good information about FA at the FA Research Alliance website, also below.
Anne Matthews, RN, PhD
Associate Professor of Genetics
School of Medicine
Case Western Reserve University