Ataxia is a term that describes a lack of muscle control or coordination of voluntary movements, such as walking and picking up objects. It is not a disease itself, but rather a symptom of an underlying condition. Ataxia can affect various parts of the body, leading to difficulties with balance, walking, swallowing, speaking, and other motor skills. Understanding what ataxia is and its potential causes is the first step in navigating this complex condition.
Ataxia can be caused by damage to different parts of the nervous system, including the cerebellum, which is the part of the brain that controls coordination. While there are various causes of ataxia, some forms are inherited. Autosomal recessive ataxias are a group of genetic conditions where an individual must inherit two copies of an abnormal gene, one from each parent, to develop the disorder. If an individual inherits only one copy, they are considered a carrier and usually do not show symptoms but can pass the gene to their children.
Several specific ataxias are inherited in an autosomal recessive manner. One well-known example is Friedreich’s Ataxia (FRDA). Named after Nikolaus Friedreich, who first identified it in 1863, FRDA is caused by a defect in the Frataxin (FXN) gene. This gene abnormality disrupts the production of frataxin, a protein essential for the proper function of mitochondria, the energy producers of cells. Individuals with FRDA inherit two copies of the faulty FXN gene, leading to progressive damage to the nervous system.
Another autosomal recessive ataxia is Ataxia Telangiectasia (A-T). This condition typically becomes apparent in early childhood when children begin to walk. While children with A-T may start walking at a normal age, they soon exhibit unsteadiness, swaying, and balance issues when walking, standing, or sitting. A hallmark of A-T is the development of telangiectasias, small, spider-like red veins that appear in the corners of the eyes and on sun-exposed areas of the skin, such as the ears and cheeks. The combination of ataxia and these distinctive telangiectasias gives the condition its name.
It’s important to note that while some ataxias are autosomal recessive, others can be inherited in different ways, such as Mitochondrial Ataxias. These are passed down from a mother to her child through defects in the mitochondria present in the mother’s egg cells. This unique inheritance pattern means that mitochondrial ataxias are maternally inherited.
Understanding the different types of ataxia and their inheritance patterns is crucial for diagnosis and genetic counseling. If you or someone you know is experiencing symptoms of ataxia, it is important to seek medical advice for proper evaluation and guidance.
