Spinocerebellar Ataxia - Causes, Symptoms, Diagnosis, and Management

Introduction

Ataxia is described as poor control of the muscle that leads to involuntary movements. An affected person may have difficulty balancing, speech, eye movements, and walking. When the cerebellum (a part of the brain that controls the coordination of the muscles) is damaged due to certain factors such as tumors, strokes, or genetic disorders can cause ataxia. There are many types of ataxia and autosomal dominant ataxias, depending on the causes and symptoms, and one is spinocerebellar ataxia.

What Is Spinocerebellar Ataxia?

Spinocerebellar ataxia is a progressive autosomal dominant condition that affects the cerebellum and sometimes the spinal cord. This condition worsens gradually and affects speech, legs, eyes, and hand coordination. Researchers have found more than 40 types of spinocerebellar ataxia, such as

• Spinocerebellar Ataxia Type 1: As the name suggests, it was the first type described, and then further subtypes were introduced. Type 1 affects around 1 to 2 per 100,000 people worldwide.

• Spinocerebellar Ataxia Type 2: Type two affected individuals may develop hearing loss and involuntary jerking movements.

What Causes Spinocerebellar Ataxia?

An inherited gene mutation can lead to different types of spinocerebellar ataxia. The gene affected in this condition is ATXN1, which gives instructions to make the ataxin 1 protein. This protein is found in many parts of the body, and its main function is unclear, but it is believed to regulate the first stage of protein production and RNA (ribonucleic acid) processing. The ATXN1 gene has one DNA (deoxyribonucleic acid)segment, CAG (cytosine, adenine, and guanine) trinucleotide repeat. When a mutation occurs, the length of the CAG trinucleotide segment increases in the ATXN1 gene.

Spinocerebellar ataxia is an autosomal dominant condition, meaning that only one set of the mutated gene from the parent can affect the child with this condition, so the child has a 50 percent chance of inheriting the defective gene.

What Are the Symptoms of Spinocerebellar Ataxia?

Some of the common symptoms include:

• Slurred speech.

• Loss of sensation.

• Involuntary eye movement.

• Difficulty walking.

• Headache.

• Dizziness.

• Trouble remembering information.

• Poor hand-eye coordination.

• Seizures.

What Are the Different Modalities Through Which Spinocerebellar Ataxia Can Be Diagnosed?

Some of the different methods through which spinocerebellar ataxia can be diagnosed include:

• Genetic Testing - It examines the DNA, which is a database that carries instructions for the body’s functions. It is always informed before genetic testing that, in some cases, the negative result does not confirm the diagnosis, and the test can be performed again. The blood test is done by a healthcare expert who takes the blood from the arm’s vein and the sample is sent to the laboratory for further testing.

• Magnetic Resonance Imaging - A brain magnetic resonance imaging (MRI) is taken to check for any abnormalities in the brain. A healthcare professional will ask the patient to lie down on the bed of the machine. Once the patient is settled, the expert will operate the machine in a different chamber. The machine will take several scans, which take around half an hour to complete. The sound of the machine will be very loud and high-pitched. The expert will be able to communicate with the patient with an intercom connected to the chambers. A headphone can be placed to listen to music to calm the patient.

• Computed Tomography (CT) Scan - The scanner’s X-ray moves around the head to capture the images from a different angle. This helps input a better view from each angle of the head.

What Are the Differential Diagnosis of Spinocerebellar Ataxia?

Due to its wide range of clinical features, there is a wide range of differential diagnoses.

• Drug-induced Movement Disorder: The dystonia related to spinocerebellar ataxia is often confused with neuroleptic drug-induced dystonia. Drugs like Benzodiazepines and Diphenhydramine cause this condition.

• Acute Viral Cerebellitis: Many viral infections affect the cerebellum and have very similar symptoms as spinocerebellar ataxia, like seizures.

• Chorea: It is an involuntary muscle movement that occurs in different conditions and is mainly associated with Huntington’s disease (a condition that affects the brain).

• Nongenetic Ataxia: One of the most common or distinctive features of SCA is ataxia. Ataxia can occur for various reasons, such as vitamin B12 deficiency and radiation exposure. The symptoms of deficiency of both these conditions are very similar.

How Is Spinocerebellar Ataxia Treated?

There is no cure for spinocerebellar ataxia, but the symptoms can be managed by following certain treatment modalities.

• Speech therapy can be given to improve slurred speech and difficulty in swallowing.

• To help in balancing and mobility, physiotherapy can be given in which different exercises and equipment are used to regain muscle strength.

• For people who have difficulty walking, even for small distances, a wheelchair or walker can be used.

• Medication can be advised to reduce stiffness, pain, and sleeping disorders.

What Are the Risk Factors that Can Lead to Spinocerebellar Ataxia?

Some of the risk factors that, if ignored, can lead to this condition include:

• Consuming alcohol for a long period of time can lead to spinocerebellar ataxia.

• Deficiency of vitamins and nutrients due to improper diet or environmental disorder.

• Viral infections include chicken pox and Episten-Barr virus (a viral infection that spreads mostly through saliva).

• Addiction to certain medications. When a medication is given after treatment or surgery for a certain amount of time, sometimes an individual gets addicted to them, which can cause many complications, such as spinocerebellar ataxia.

Conclusion

Spinocerebellar ataxia is a condition that affects the cerebellum, which is an essential part of the brain. It leads to abnormal movements of hands, eyes, muscles, and speech and sometimes affects the normal motor growth of an individual. If any similar symptoms to this condition are seen, they should be immediately informed by the doctor. Different methods like imaging tests and genetic testing can easily diagnose it. Though many people panic that this condition has no treatment, if diagnosed early, the symptoms can be controlled, which will help them recover and gain physical strength faster.