What is the Greenfield classification of olivopontocerebellar atrophy (OPCA)?

Updated: Dec 17, 2018
  • Author: Sombat Muengtaweepongsa, MD, MSc; Chief Editor: Selim R Benbadis, MD  more...
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In 1954, Greenfield proposed a new clinicopathological classification of OPCA. [6] This was revised by Harding in 1982, based on anatomical, pathological, and biochemical features. [7] As applied to the purely autosomal dominant ataxias, the classification is as follows:

  • Type 1 ADCA (ADCA-1) - Ataxia and noncerebellar findings (eg, pyramidal or extrapyramidal dysfunction and ophthalmoplegia)

  • Type 2 ADCA (ADCA-2) - Similar to ADCA-1 but includes retinal degeneration

  • Type 3 ADCA (ADCA-3) - Includes relatively pure cerebellar dysfunction

In the ADCA grouping, the OPCAs are found in ADCA-1 and ADCA-2.

Harding was well aware that this was essentially a phenotypic grouping that lumped a number of different genetic diseases into 3 classes. However, the system was valuable for further genetic and other scientific work, in which Harding herself has been a significant contributor.

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