Spinocerebellar Ataxia (SCA)
Description
Spinocerebellar ataxia (SCA) is a group of inherited neurodegenerative disorders that primarily affect the cerebellum, a part of the brain responsible for coordinating movement. These disorders lead to a progressive loss of balance, coordination, and muscle control, affecting various aspects of daily life. This blog provides a comprehensive overview of SCA, covering its signs and symptoms, causes, inheritance patterns, diagnosis, management strategies, and tips for thriving with the condition.
Genes Involved
There are over 40 known genes associated with different types of SCA. Some of the most common genes involved include:
- ATXN1: Responsible for SCA1
- ATXN2: Responsible for SCA2
- ATXN3: Responsible for SCA3 (also known as Machado-Joseph disease)
- ATXN7: Responsible for SCA7
- ATXN10: Responsible for SCA10
- CACNA1A: Responsible for SCA6
- FOX2: Responsible for SCA15
Recognizing the Signs and Symptoms
The signs and symptoms of SCA vary depending on the specific type and severity, but common features include:
- Progressive difficulty with balance and coordination: This can manifest as unsteady gait, frequent stumbling, difficulty walking, and problems with fine motor skills like writing or buttoning clothes.
- Speech problems: Slurred speech, difficulty forming words, and a soft voice are common.
- Eye movement difficulties: Nystagmus, a rapid, involuntary eye movement, can occur.
- Muscle weakness and atrophy: This can affect the limbs, leading to difficulty with activities like climbing stairs or carrying objects.
- Cognitive decline: Some individuals with SCA may experience mild cognitive impairment, affecting memory, attention, and executive function.
- Other symptoms: Sensory disturbances, including numbness or tingling, can also occur.
Causes
SCAs are caused by mutations in specific genes that produce proteins involved in the function and survival of neurons in the cerebellum and other parts of the brain. These mutations lead to the accumulation of abnormal proteins that damage and ultimately kill neurons, causing the progressive neurological deterioration characteristic of SCA.
Inheritance/recurrence risk
Most SCAs are inherited in an autosomal dominant pattern, meaning that if one parent carries the mutated gene, there is a 50% chance of their child inheriting the mutation and developing the disorder. In some cases, SCAs may be inherited in an autosomal recessive pattern, requiring both parents to carry the mutation for the child to be affected.
