Tracking Our Progress...LCP

Editor's note; This is part two of Dr. Olivry's article. Definition, epidemiology, clinical signs, and diagnosis of the disease were covered in the Summer issue.

Legg-Calve-Perthes (LCP)
Disease and Potential Association with Mucopolysaccharidosis (MPS) in Dogs

Summer 2004, NEWS

University of Pennsylvania

The Section of Medical Genetics at the University of Pennsylvania is currently involved in research on Mucopolysaccharidosis and its association with Legg-Calve-Perthes (LCP), a degenerative orthopedic disease. Based on a survey by the AKC Canine Health Foundation, LCP is considered to be a major health problem and is also known as femur head necrosis. Because of impaired blood supply in the hip, the femur heads are denied oxygen and various essential nutrients, and hence, a femoral head necrosis ensues.

LCP often affects small breed dogs, such as Shetland Sheep Dogs, Miniature and Toy Poodles, Dachshunds, Pekingese, Manchester Terriers, West Highland White Terriers, Lakeland Terriers, Parson Russell Terriers, Wirehaired Fox Terriers, Border Terriers, Cairn Terriers, Australian Terriers, Scottish Terriers, Silky Terriers, Welsh Terriers, Yorkshire Terriers, Boston Terriers, Cocker Spaniels, Miniature Pinschers, Miniature Schnauzers, Pomeranians, Affenpinschers, Bichon Frises, Schipperkes, Italian Greyhounds, Chihuahuas, Pugs, and others.

Usually dogs with LCP develop signs that include lameness, often confined to one of the hind limbes, and reluctance to run or jump. These signs typically appear in affected dogs under one year of age. Unfortunately, the exact cause of LCP is still unknown, and there is no laboratory test or cure for LCP. Mildly affected dogs may be able to live with pain medication and by restricting their activity, but dogs that are severely affected often must undergo surgical femoral head resection.

LCP is often confused with hip dysplasia, since the clinical signs presented by affected dogs are similar. However, there is a group of diseases called the mucopolysac-charidoses (MPS) that commonly result in skeletal abnormalities and degeneration of the hip. Because an enzyme is missing, the polysaccharides (large sugars) that would normally be degraded by this enzyme accumulate, hence the term lysosomal storage disease, and are excreted in the urine. The build up polysaccharides causes skeletal abnormalities, including defects in the hip joints similar to LCP. In fact, several Miniature Pinschers with MPS VI were operated on for LCP disease and were later found to have MPS VI and additional skeletal abnormalities.

Currently, the Section of Medical Genetics is interested in studying whether or not LCP and MPS are related, that is, if some forms of LCP are really just the manifestations of MPS. As the cause or causes of LCP are not fully understood at the present time, this study seeks to determine one possible cause of LCP.

A simple urine test, known as an MPS spot test, is currently available to screen for the presence of polysaccharides in a dog's urine and thereby possibly determine if a dog has MPS disease. We are, therefore, asking that breeders, pet owners, and veterinarians of dogs who have been diagnosed with or suspected of having LCP to please submit a urine sample from the affected dog as well as radiographic report from the referring veterinarian to Penn's Metabolic Screening Laboratory. Two-to-five milliliters of fresh or freshly frozen urine should be shipped in a well-sealed container labeled with the dog's name with an ice pack by two-day express mail. Testing of dogs known or suspected of having LCP disease, with appropritae clinical information, is free. All results from the urine tests of individual dogs will be kept strictly confidential and will only be reported to the owners or veterinarians of the affected dog.

For further information, contact Dr. Urs Giger or Lisa Berman at penngen@mail.vet.upenn.edu or phone 215-898-9994; samples may be sent to Dr. Urs Giger at Room 4006 VHUP, 3900 Delancey Street, Philadelphia, PA 19104-6010.