Causes and Inheritance of Friedreich Ataxia

CAUSES Friedreich’s ataxia (FA) is caused by defects (mutations) in the gene for the protein frataxin. Genes are recipes for making proteins, which provide structure to our cells and drive the chemical reactions inside them. Scientists believe the frataxin protein regulates the levels of iron inside mitochondria — tiny cellular “factories” that use oxygen to produce energy. INHERITENCE Upon hearing a diagnosis of FA, people often reasonably ask, “But it doesn’t run in our family, so how could it be genetic?” The answer is that the mutations underlying FA can run silently through a family, because the disease is inherited in an autosomal recessive pattern. Autosomal refers to the fact that the frataxin gene is on chromosome 9, one of the 22 pairs of autosomes (chromosomes other than the X or Y). Recessive means it takes two defective copies of the frataxin gene to cause FA, with one copy inherited from each parent, neither of whom would normally have FA symptoms.