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What is Olivopontocerebellar atrophy and explain in detail?
Olivopontocerebellar atrophy (OPCA) is the degeneration of neurons in specific areas of the brain – the cerebellum, pons, and inferior olivary nucleus. OPCA is present in several neurodegenerative syndromes, including inherited and non-inherited forms of ataxia (such as the hereditary spinocerebellar ataxia known as Machado–Joseph disease) and multiple system atrophy (MSA), with which it is primarily associated.OPCA  may also be found in the brains of individuals with prion disorders and inherited metabolic diseases.  The characteristic areas of brain damage that indicate OPCA can be seen by imaging the brain using CT scans or MRI studies.The term was originally coined by Joseph Jules Dejerine and André Thomas.

Signs and symptoms
OPCA is characterized by progressive cerebellar ataxia, leading to clumsiness in body movements, veering from midline when walking, wide-based stance, and falls without signs of paralysis or weakness. Clinical presentation can vary greatly between patients, but mostly affects speech, balance and walking.  Other possible neurological problems include spasmodic dysphonia, hypertonia, hyperreflexia, rigidity, dysarthria, dysphagia and neck dystonic posture.

Cause
Olivopontocerebellar atrophy is hereditary, but has an unknown genetic basis