How Is Friedreich Ataxia Inherited? Risk to Children

Friedreich ataxia (FRDA) is an autosomal recessive genetic condition ^[1]. If you have Friedreich ataxia, you will pass one of your pathogenic (disease-causing) variants to your children ^[2]. Whether your child develops the condition depends on your partner’s genetic status ^[3]. While inheriting two pathogenic variants means a child will develop FRDA, they may not show symptoms at birth, as the age of onset and disease severity can vary significantly ^[4].

Understanding Autosomal Recessive Inheritance

Genes come in pairs. You inherit one copy from your mother and one from your father. The gene responsible for Friedreich ataxia is called the FXN gene.

In an autosomal recessive condition like Friedreich ataxia, a person must have a pathogenic variant in both copies of their FXN gene to develop the disease ^[2]. Most commonly, this involves a specific change called a GAA-repeat expansion on both copies, though some people have an expansion on one copy and a different type of pathogenic variant (such as a sequence change or deletion) on the other ^[1][3].

A carrier is someone who has one non-pathogenic (working) FXN gene and one pathogenic variant ^[5]. Carriers do not have symptoms of Friedreich ataxia, but they can pass the variant to their children ^[4].

Because you have Friedreich ataxia, both of your FXN genes have pathogenic variants. This means you will pass a variant to every child you have. Therefore, the risk to your future children is determined primarily by your partner’s genetics ^[2].

While carrier frequencies vary by geographic location and ancestry, some research estimates that about 1 in 100 people in certain populations are carriers ^[4]. For example, a Norwegian study estimated a carrier frequency of 1 in 196 ^[6]. However, population estimates are not a substitute for personal genetic testing ^[7].

Your Family Planning Scenarios

Assuming your partner’s genetic status is confirmed through accurate testing, the inheritance chances apply independently to each pregnancy ^[4]:

Note: No test can detect 100% of all possible FXN variants. A negative carrier test greatly reduces the risk but leaves a very small “residual risk” that your partner could still carry a rare variant ^[8][5].

Comprehensive Partner Testing

If you are considering having children, it is strongly recommended to arrange genetic counseling and testing for your partner ^[5]. A basic “carrier screen” may only look for the most common GAA-repeat expansions ^[8]. However, testing should be comprehensive and guided by your own molecular report ^[3]. Depending on your specific variants, your partner’s testing may need to include both GAA-repeat expansion analysis and additional sequencing or deletion/duplication analysis ^[8][7].

Family Planning and Reproductive Options

A genetic counselor can help you navigate these testing options and discuss family planning alternatives ^[3][9]. There is no single “right” reproductive choice, and options vary by personal preference, emotional readiness, cost, and availability:

• Prenatal Diagnostic Testing: Procedures like chorionic villus sampling (CVS) or amniocentesis can test an ongoing pregnancy for the specific familial FXN variants ^[5].
• IVF with Preimplantation Genetic Testing (PGT-M): This involves using in-vitro fertilization and testing embryos for the familial variants before pregnancy ^[5]. This requires a laboratory to establish a test for your specific variants, involves the medical procedures of IVF, and does not guarantee implantation or a successful pregnancy.
• Other Options: Families may also consider using donor sperm or donor eggs from non-carriers, adoption, or choosing to conceive without genetic selection ^[3].

A Note on Preconception Health: Genetic risk is only one part of family planning. Because Friedreich ataxia is a complex condition that can involve heart and neurological symptoms, pre-pregnancy consultations with neurologists and cardiologists are vital to evaluate pregnancy safety, maternal health, and medication use ^[1].