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Cerebellar Purkinje Cell Degeneration
The central nervous system (CNS) is composed of both white and gray matter. These can be divided into spinal cord and brain white or gray matter. Gray brain matter is positioned at the periphery, or cortex of the cerebrum and cerebellum, and it is made up of three layers. The neurons (nerve cells) of the outer (molecular) and inner (granular) layers are small. The major function of the cerebellum is to coordinate voluntary, postural and reflex movements. It coordinates motor activity that is initiated elsewhere, (coordination NOT initiation). The cerebellum also assists with the maintenance of equilibrium.
The Purkinje cell middle layer of the cerebellar cortex is composed of Purkinje cells. Purkinje cells are the only cortical neurons whose axons extend through the white matter.
Cerebellar Purkinje cell degeneration is a progressive genetic (autosomal recessive) disease of the central nervous system marked by degeneration of virtually all cerebellar Purkinje cells, which was characterized by extensive loss and degeneration of Purkinje neurons. This rocess results in a condition called cerebellar cortical atrophy.
SIGNS
Growth retardation, and progressive ataxia (lack of muscle coordination; animals may stand with a broad-based stance; truncal ataxia (swaying of the body) may be present.), tremors, dysmetria (most common is hypermetria, a spastic, high stepping "over-measurement" gait in all four limbs; hypometria may also be seen.), nystagmus, progressive gait abnormalities, and diluted coat color (in some breeds). Littermates with nondiluted coat color are neurologically normal. The signs of incoordination in CA affected Scottish Terriers have been recognized by owners or breeders as early as 10 weeks of age, and as late as 4 years of age. Recognition of clinical signs has more to do with the severity of the disorder than the actual onset of cerebellar degeneration. Many affected dogs remain with mild incoordination their entire lives, and live out a normal life span. Other affected dogs progress to the point where they can not walk without assistance (as older dogs) due to the disorder.
A syndrome of cerebellar Purkinje cell degeneration and coat color dilution was diagnosed in a family of Rhodesian Ridgeback dogs, Staffordshire terrier. A slowly progressing late-onset form of cerebellar degeneration develops in OESD, and the mode of inheritance is by an autosomal recessive gene. Epilepsy was reported in several litters of Lagotto Romagnolo dogs which was associated with loss of Purkinje cells.
The term abiotrophy refers to spontaneous, premature neuronal death. In most abiotropies, an inherited inborn error of metabolism (usually unidentified) is considered to be responsible. Most abiotrophies involve the cerebellar Purkinje cells, which appear to be exquisitely susceptible to derangements of their metabolism. Abiotrophies may affect the cerebellum alone or may affect the cerebellum and other areas of the brain. Cerebellar abiotrophies have been identified in cats and in many dog breeds including Kerry Blue terrier, Gordon setter, rough coated Collie (autosomal recessive inheritance) and Brittany spaniel.
Adapted from
1. Cerebellar Purkinje's cell degeneration and coat color dilution in a family of Rhodesian Ridgeback dogs.Chieffo C, Stalis IH, Van Winkle TJ, Haskins ME, Patterson DF.
2. Cerebellar degeneration in Old English Sheepdogs. H. Steven Steinberg , VMD, DACVIM Thomas Van Winkle , VMD, DACVP Jerold S. Bell , DVM Alexander de Lahunta , DVM, PhD, DACVIM
3. Benign Familial Juvenile Epilepsy in Lagotto Romagnolo Dogs
T.S. Jokinen, L. Metsa¨honkala, L. Bergamasco, R. Viitmaa, P. Syrja¨ , H. Lohi, M. Snellman, J. Jeserevics, and S. Cizinauskas
4. Open Letter from Dr. Bell, DVM. Scottish Terrier Club of America.
5. Cerebellar Diseases of Dogs and Cats. Richard A. LeCouteur, BVSc, PhD, Diplomate ACVIM (Neurology), DECVN
Go Pets America recommends seeking the advice of your local veterinarian for the most appropriate vaccination program and for the diagnosis and treatment of your pet's health problems. For vaccination requirements please contact your state and local licensing authorities.
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Cerebrum - the higher brain cells; the chief portion of the brain controlling concious thoughts and actions
Cerebellum - the inferior part of the brain located beneath the cerebrum; it is responsible for muscular coordination.
Dysmetria - an abnormal condition that prevents from properly measuring distances associated with muscular acts and from controlling muscular actions. Dysmetria of the head produces an "intention tremor". This is a tremor that appears after initiation of and during a movement.
Nystagmus - a rapid, rhythmic side-to-side movement of the eyeball seen in diseases of the brain.
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