Olivopontocerebellar Atrophy

Synonyms Hereditary OPCA Disorder Subdivisions OPCA1 OPCA, Menzel type Spinocerebellar Ataxia 1 SCA1 OPCA2 OPCA, Holguin type Spinocerebellar Ataxia 2 SCA2 SCA, Cuban type OPCA3 Spinocerebellar Ataxia 7 SCA7 OPCA with retinal degeneration OPCA, Fickler-Winkler type OPCA4 OPCA, Schut-Haymaker type OPCA5 OPCA with dementia and extrapyramidal signs General Discussion Hereditary olivopontocerebellar atrophy (OPCA) is a rare group of disorders characterized by progressive balance problems (disequilibrium), progressive impairment of the ability to coordinate voluntary movements (cerebellar ataxia), and difficulty speaking or slurred speech (dysarthria). There are at least five distinct forms of hereditary OPCA. All forms of hereditary OPCA, except one, are inherited as autosomal dominant traits. The term olivopontocerebellar atrophy has generated significant controversy and confusion in the medical literature because of its association with two distinct groups of disorders, specifically multiple system atrophy (MSA) and spinocerebellar ataxia (SCA). OPCA may refer to a specific form of MSA or one of several types of SCA. Hereditary OPCA refers to the group of disorders that overlaps with SCA. Both forms of OPCA are characterized by progressive degeneration of certain structures of the brain, especially the cerebellum, pons, and inferior olives. The cerebellum is the part of the brain that plays a role in maintaining balance and posture as well as coordinating voluntary movement. The pons is part of the brainstem and contains important neuronal pathways between the cerebrum, spinal cord, and cerebellum. The pons serves as a relay point for messages between these structures. The inferior olives are two round structures that contain nuclei that are involved with balance, coordination and motor activity.