NEUROMUSCULAR CASE OF THE MONTH - SEPTEMBER 2005

UPDATE: Genetic Test Now Available For Pyruvate Dehydrogenase Phosphatase1(PDP1) Deficiency in Clumber and Sussex Spaniels
Contributed by Dr. Jessie Cameron
Hospital for Sick Children, Toronto, Ontario, Canada
And
Dr. Diane Shelton
University of California, San Diego

UPDATE : Testing is now available for PDP1 deficiency at the University of Missouri- Columbia. Instructions for Sample Submissions are available at www.caninegeneticdiseases.net. Charge for testing is $40.00 per sample. Questions about testing should be addressed to Liz Hansen at HansenL@missouri.edu

Thanks to Fred and Lupe (pictured below) and their dedicated owners, we have now identified a novel cause of pyruvate dehydrogenase phosphatase 1(PDP1) deficiency in Clumber and Sussex spaniels.Many thanks also to the numerous owners and breeders that have provided blood samples on their dogs for genetic testing. Due to the overwhelming response, we now have all the information needed to firmly document this mutation and the heritability. While PDP1 deficiency is rare in Clumber and Sussex spaniels and usually presents as exercise intolerance, in humans it is a debilitating disease with severe neurological symptoms. PDP1 deficiency in both breeds appears to be less severe than its human counterpart, with central neurological signs not yet identified.  However, the affected dogs do have dramatic exercise intolerance and may have a shortened life span resulting from heart and lung complications.There is also some indication that this mutation may be involved with early fetal death or death in the neonatal period.

FRED

LUPE

            PDP1 is an enzyme that is present in every cell in the body. PDP1 is located in the mitochondria, the “powerplant” of the cell. It is within the mitochondria that the body converts food into energy, which is vital not only for muscle function, but for survival.

            Recent research into PDP1 deficiency in Clumber and Sussex spaniels has led to identification of the first gene responsible for this disease in dogs, and because of this, genetic testing is now available to diagnose affected dogs, as well as providing genetic carrier status diagnosis. This disease affects both males and females, and is not X-linked. So far, genetic carriers appear to be physically normal, and the only way to identify carriers is by genetic testing. Sussex spaniels, closely related to Clumber spaniels, are also affected with PDP1deficiency, and the same mutation is present in both breeds.

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