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Is Multiple System Atrophy Inherited?

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder ¹ that occurs commonly in adults aged more than 30 years. MSA is also known as progressive autonomic failure with multiple system atrophy/ Shy-Drager syndrome (SDS)/ sporadic olivopontocerebellar atrophy (sOPCA). MSA patients can have symptoms similar to Parkinson disease (parkinsonism features) such as tremors, rigidity, bradykinesia, and imbalance or cerebellar symptoms such as difficulty in performing voluntary movements, maintaining balance and impairment of autonomic functions (heart rate, blood pressure, bladder and bowel movements). If the individual has more Parkinsonism features then the disorder is called MSA-P (Parkinsonism), if the individual has more cerebellar features then the disorder is called MSA-C (cerebellar).

Most cases of multiple system atrophy are sporadic which means multiple system atrophy occurs in people with no family history of multiple system atrophy. It can be due to a mutation or variation that occurred and not a mutation that has been passed from parents. However, there are few cases reported about familial MSA, but the exact inheritance pattern or how it can run in the family has not been identified. Many studies are being conducted in order to find the exact etiology and the pathogenesis of multiple system atrophy and these studies are still ongoing.

Causes Of Multiple System Atrophy

Multiple system atrophy is a very complex condition and it is believed that multiple system atrophy is a multifactorial disease caused by genetic, environmental and lifestyle factors. Some of the causes are identified and some are not.²

Several genes are being identified as possible risk factors to develop multiple system atrophy. SNCA (synuclein alpha) and COQ2 (coenzyme Q2, polyprenyltransferase) genes are among them. The SNCA gene gives instructions for the production of the protein called alpha-synuclein which is found in large quantities in the normal human brain whose function is not known clearly. It is usually, found at the tips of the nerve cells and it might play a role in the signal transmission from one nerve cell to another and regulate the release of dopamine. Studies have shown that variations or mutations in the SNCA gene are at an increased risk of getting multiple system atrophy in European descent. It is not still found out if these gene changes in other populations also lead to multiple system atrophy.

The COQ2 gene gives instructions for the production of coenzyme Q2 protein. The Q2 protein plays an important role in the energy production of the cells. Variations and mutations in the COQ2 gene have been related to MSA in Japanese descendent people. A link between the COQ2 gene and MSA has not been identified in other populations yet. Also, it is still unclear how exactly variations in SNCA and COQ2 lead to the development of multiple system atrophy.

Research studies suggest that environmental factors can also contribute to the manifestation of multiple system atrophy or increase the risk of getting MSA. Studies suggest that exposure to certain types of plastic or metals, solvents, and other toxins can be associated with MSA. These associations have not been confirmed yet by doing further experiments and trials.

In all cases of multiple system atrophy clumps of abnormal alpha-synuclein protein is found in many parts of the brain and spinal cord. These abnormal cells (known as inclusions) damages the normal cells which control coordination, autonomic functions, and balance. The symptoms and signs arise because of this reason.

Conclusion

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder that occurs commonly in adults aged more than 30 years. Some patients only have a mild form of the disease and in some, the disease can be severe and can lead to fatal complications. The exact etiology or pathogenesis of MSA is still unknown. It is believed to be multifactorial and caused by genetic, environmental and lifestyle factors. Several genes are being identified as possible risk factors to develop multiple system atrophy. SNCA and COQ2 genes are among them. People with variations and mutations in these genes are at an increased risk of getting multiple system atrophy. An exact inheritance pattern has not been found in MSA; most cases are sporadic. However, there are few reported familial cases but the exact inheritance pattern is not known.

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Is Multiple System Atrophy Inherited?