The Multiple Phenotypes of CBS/CBD (Boeve article)

This review article by Dr. Brad Boeve of Mayo Rochester, one of the world’s experts in CBS/CBD, is a good one. It’s a short summary of our current knowledge about CBS and CBD.

Here are a few highlights:

* When thinking of CBS and CBD, “[there] are few other syndromes and diseases in the neurodegenerative disease field that are as complex and frustrating for patients, their relatives, the clinicians involved in their care, the pathologists who analyze tissue, and the scientists devoted to their study.”

* There are primarily six clinical syndromes that are associated with CBD pathology:

#1 behavioral variant frontotemporal dementia
#2 progressive apraxia of speech or progressive aphasia syndrome (PNFA is the most common though SD and LPA can occur) [PNFA = progressive nonfluent aphasia. SD = semantic dementia. LPA = logopenic progressive aphasia] #3 corticobasal syndrome
#4 PSP Richardson syndrome [PSP = progressive supranuclear palsy] #5 dementia syndrome highly consistent with probable Alzheimer’s Disease
#6 posterior cortical atrophy

There are “other rare variants” besides these six.

* The clinical syndrome CBS has many underlying diseases or pathologies associated with it — CBD, PSP, AD, Pick’s Disease, etc. “On one level, this heterogeneity is difficult to explain, yet a unifying pathologic feature of all of these diseases is the maximal involvement of the parietofrontal cortex and their afferent and efferent projections. The topographic distribution of neurodegeneration, therefore, dictates the clinical syndrome.”

I’ve copied the abstract below.

Robin

Here’s the abstract:

Journal of Molecular Neuroscience. 2011 Aug 19. [Epub ahead of print]

The Multiple Phenotypes of Corticobasal Syndrome and Corticobasal Degeneration: Implications for Further Study.

Boeve BF.
Divisions of Behavioral Neurology and Movement Disorders, Department of Neurology, Mayo Clinic, Rochester, MN, USA

Abstract
Corticobasal degeneration (CBD) is a complex neurodegenerative disorder which nomenclature of which its nomenclature and characterization continues to evolve. The core clinical features that have been considered characteristic of the disorder include progressive asymmetric rigidity and apraxia, with other findings suggesting additional cortical (e.g., alien limb phenomena, cortical sensory loss, myoclonus, and mirror movements) and basal ganglionic (e.g., bradykinesia, dystonia, and tremor) dysfunctions.

The characteristic findings at autopsy are asymmetric cortical atrophy that is typically maximal in the frontoparietal regions, as well as basal ganglia and nigral degeneration.

Microscopically, abnormal accumulations of the microtubule-associated tau protein are found in both neurons and glia, and this disorder is now considered one of the “tauopathies.”

CBD was initially thought to represent a distinct clinicopathologic entity. Recent studies have shown considerable clinicopathologic heterogeneity, leading some to use the term “corticobasal syndrome” (CBS) for the constellation of findings initially considered characteristic of the disorder, and the term “corticobasal degeneration” for the histopathologic disorder.

In this review, the multiple phenotypes/syndromes associated with CBD pathology, and multiple diseases associated with the CBS, are presented. The clinicopathologic heterogeneity in CBS/CBD and the implications of this heterogeneity on clinical practice, on understanding the focal/asymmetric cerebral degeneration syndromes, and on future research are all reviewed.

PubMed ID#: 21853287 (see pubmed.gov for this abstract only)