What is the definition of Olivopontocerebellar Atrophy?
Olivopontocerebellar atrophy (OPCA) is a term used for a progressive condition characterized by the degeneration of nerve cells (neurons) in specific areas of the brain. OPCA can be viewed as a finding of several diseases, and indicates a form of progressive ataxia (abnormal or uncontrolled movements) distinguished by characteristic findings in brain imaging studies and at autopsy (pontine flattening and cerebellar atrophy). It was traditionally divided in hereditary or genetic OPCA and sporadic OPCA. Currently, most of the major forms of hereditary OPCA refer to disorders that overlap with spinocerebellar ataxia (SCA), which is a neurological disorder characterized by ataxia. The sporadic forms are considered now to be a form of multiple system atrophy (MSA). OPCA may also occur in people with prion disorders and inherited metabolic diseases. The main symptom is clumsiness that slowly gets worse. Other symptoms may include problems with balance; speech or swallowing problems; difficulty walking; abnormal eye movements; muscle spasms; and neuropathy. Whether OPCA is inherited (and the inheritance pattern) depends on the underlying cause, if known. There is no cure for OPCA, and management aims to treat symptoms and prevent complications.
What are the alternative names for Olivopontocerebellar Atrophy?
What are the causes for Olivopontocerebellar Atrophy?
Olivopontocerebellar atrophy (OPCA) can occur in association with disorders caused by inherited genetic mutations (hereditary OPCA), or it can be sporadic. Many specific genes have been identified for the genetic forms, although exactly how each genetic abnormality leads to the specific symptoms of OPCA often is not known. Sporadic OPCA refers to disorders for which there is not yet evidence of a hereditary component or genetic cause.
The subtypes of hereditary OPCA and their genetic causes (when known) can be viewed in tables on Medscape Reference's website here by scrolling down or clicking on "Tables" in the left-hand menu.
How is Olivopontocerebellar Atrophy diagnosed?
A diagnosis of olivopontocerebellar atrophy (OPCA) may be based on a thorough medical exam; the presence of signs and symptoms; imaging studies; various laboratory tests; and an evaluation of the family history.
MRI of the brain may show characteristics of OPCA, such as specific changes in the size of affected parts of the brain. This is more likely as the disease progresses; it is possible to have OPCA and have a normal brain MRI (especially within the first year of symptom onset).
Hereditary OPCA may be suspected based on having a family history, and may be diagnosed by genetic testing (when available) for the condition suspected or known to be present in the family. Sporadic OPCA may be diagnosed if hereditary forms of OPCA, and other conditions associated with OPCA, have been ruled out.
Is Olivopontocerebellar Atrophy an inherited disorder?
Olivopontocerebellar atrophy (OPCA) may be associated with conditions that are inherited (genetic), or it may occur sporadically.
Genetic forms of OPCA may be inherited in an autosomal dominant, autosomal recessive, or X-linked manner. The inheritance pattern depends on the specific genetic cause. For example, OPCA associated with spinocerebellar ataxia 3 is caused by a mutation in the ATXN3 gene and is inherited in an autosomal dominant manner. Most types of inherited OPCA are associated with spinocerebellar ataxias that follow autosomal dominant inheritance.
Sporadic OPCA refers to when the condition occurs for unknown reasons, or when there is no evidence of a genetic basis. Some people with sporadic OPCA will eventually develop multiple system atrophy (MSA).
People with a personal or family history of OPCA are encouraged to speak with a genetic counselor or other genetics professional. A genetics professional can evaluate the family history; address questions and concerns; assess recurrence risks; and facilitate genetic testing if desired.