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Cystinuria in Mastiffs - Frequently Asked Questions (FAQ)

Questions & Answers

What is Cystinuria? Cystinuria is an inherited disease that has been found in Mastiffs. Cystinuria is caused when the kidneys cannot properly filter and transport certain amino acids, including cystine, in the kidney tubules. This causes abnormally high levels of cystine in the urine. The cystine isn't able to break down in acidic urine and the excess urinary cystine may cause cystine crystals (sandy grit) and possibly cystine stones to form in the kidney and/or bladder.

How do you pronounce Cystinuria? Cystinuria is pronounced: sis-teen-yoor-ee-ah or sis-tin-yoor-ee-ah

What are the symptoms of Cystinuria? Cystinuric animals may not exhibit any obvious signs at all, or they may show recurrent clinical signs of a urinary tract disorder at any age or never. They may experience difficulty in urination, have blood tinged urine, pass crystals or calculi (stones that may cause pain and infection), or they may be unable to urinate, despite numerous attempts. Due to the their urogenital anatomy, male dogs may become completely blocked. If a blockage occurs, the dog's bladder may become extremely distended and it may be at risk of rupturing. This has been known to happen. A complete blockage can also lead to kidney failure and death, even prior to the bladder rupture.

Do all dogs that have Cystinuria show symptoms of the disease? No. Many animals with Cystinuria can go years without showing any symptoms at all. This is especially common in bitches. A dog cannot be assumed to be free of Cystinuria no matter what age it has reached without becoming blocked.

Is there a test for Cystinuria in Mastiffs? Yes. The University of Pennsylvania (UPenn) offers a special urinary screening test for the diagnosis of Cystinuria in Mastiffs. This test is called the nitroprusside spot test, which is different than the routine urinalysis veterinarians and veterinary diagnostic laboratories offer. The test is very simple and the breeder or the pet owner can do sample collection at home. Simply collect a clean urine sample in whatever way you find most convenient. We have found that pie plates work well for bitches and a clean paper cup, even taped to the end of a stick, works great for dogs. Follow the directions for submission found on the submission form and later in this FAQ.

How prevalent is Cystinuria in mastiffs? UPenn Cystinuria statistics as of September 29, 2000: Total tested 220 Negative 90.9 % Positive 9.1 % Of the affected: 90 % males 10 % females Previously: "Of the urine samples which we have tested from Mastiffs, 19 out of 145 were either nitroprusside positive or had abnormally elevated cystine levels when directly measured. This does not mean that we have diagnosed 19 affected animals, as we are not sure what the urine amino acid pattern will be for carrier animals. It just means that they are abnormal and could be from affected or possibly carrier animals (depending on how this disease is inherited)." That works out to 13% having abnormal levels of cystine, or roughly one in 7 Mastiffs.

How do I submit a urine sample? You can get a copy of the Cystinuria Submission Form at: Mastiff Cystinuria urine submission form. Collect a small amount of urine (approximately 3cc) in a very clean container. For instance, a sterile glass or plastic tube with appropriate lids, which should be available at your local veterinarian's office. Ship by overnight mail (example: Federal Express) in a Styrofoam container with an ice pack, all within a sturdy cardboard box (per FedEx regulations). Make sure that you include the Cystinuria submission form and a check payable to: Trustees, Univ. of Penn. for $18 per sample. Joesephine Duebler Genetic Disease Testing Laboratory Cystinuria Veterinary Hospital Room 4020 University of Pennsylvania 3900 Delancey Street Philadelphia, PA 19104-6010

Does a veterinarian have to submit the Cystinuria test to UPenn? No. Anyone can collect a urine sample and send it to UPenn.

How do I reach UPenn if I need to talk to them directly? UPenn and the MCOA Cystinuria Committee discourage calling UPenn directly unless it is an emergency or your veterinarian needs a consultation. Calling UPenn directly may cause a delay in their research efforts, which unnecessarily affects their ability to map the gene for us and to eliminate the disease from our gene pool. Please, first call or e-mail the MCOA Cystinuria Subcommittee Chairperson for routine questions, answers, directions or support. You may also call or e-mail one of the MCOA Cystinuria Committee Members. If your veterinarian feels that it is necessary to speak directly to UPenn, have him/her phone UPenn at: (215) 898-8078 or Fax: (215) 573-2162 Thankfully, the word is getting out about this potentially fatal disease. The down side is that UPenn's efforts have been slowed considerably by concerned owners and breeders calling them directly with general questions which anyone on the committee can answer. Confidentiality is absolutely assured.

If the test is positive does that mean my Mastiff is affected? A positive test result means that your Mastiff has not been able to properly process the amino acid, cystine. This is the problem that can result in formation of stones and a potentially life-threatening situation for your dog. There have, to date, been NO FALSE POSITIVES. This does not mean, however, that your dog will definitely form stones and require surgery. You should take action to make dietary changes as necessary and keep track of the acidity level in the urine of positive animals for their health and safety. Breeding these animals must also be considered carefully, as this disease does have a genetic basis.

My Mastiff has reoccurring UTIs, but his Cystinuria test came back negative. Does this mean he definitely doesn't have it? The test can be influenced by several variables. If you had a negative result at one time, but your dog subsequently had signs of urinary tract disease, a retest is a good idea and highly recommended.

Are the results kept confidential? YES. All information and testing results will be kept strictly confidential.

How long does it take to get the test results back? Results are available within 1 to 4 weeks from receipt of samples and they will be sent to the owner (approximately 3 to 6 weeks from shipping sample). In the case of an emergency, results can be faxed or given over phone. Make sure you include your phone number or your vet's phone number and fax number incase the results need to be expedited. On routine screenings, please allow the full four weeks before having your vet call for results.

Is there a test that can show if Mastiffs are affected, carriers or clear of Cystinuria? There is a DNA test for Cystinuria in Newfoundlands that can detect those that are affected, carriers and clear of the disease, but this test is not yet available for Mastiffs. UPenn has generously been researching the disease in Mastiffs and they need our participation to develop the same type of test in Mastiffs. Whether or not there is a carrier state depends on the type of inheritance of this disease in Mastiffs. We simply need more data and research to nail this down. Your participation can make all of the difference.

At what age can I do the Cystinuria testing on my Mastiffs? Puppies can be tested as young as 4 weeks of age. UPenn will only charge $10 per sample on puppies between 4 and 12 weeks of age, if 5 or more puppies are tested at the same time. Currently, UPenn is recommending that Mastiffs be retested after the age of 18 months and prior to breeding. How do you collect urine from young puppies? Puppies may be stimulated to urinate by applying a wet cotton ball in their urogenital area. Once they begin urinating, you can collect the urine in a clean container.

What if I can't collect enough urine? You can collect the urine and store it in a freezer until you have collected enough of it to submit to UPenn. The test requires a minimum of 3-5 cc of urine. There is no need to send more than 10 cc.

How much does UPenn charge for the Cystinuria test? The test is only $18 plus shipping for those Mastiffs being tested for screening purposes or for pre-breeding testing. As mentioned previously, UPenn will only charge $10 per sample on puppies between 4 and 12 weeks of age if 5 or more puppies are tested at the same time. In order to avoid additional shipping charges, you can submit several samples in one shipping container.

Is there anything I can do to help prevent Cystinuria in Mastiffs? Yes. Please test your Mastiffs and their offspring! If any of them are affected, consider your options carefully before using them in your breeding program. Remember, this is an inherited disease. Send a blood sample and a copy of the affected Mastiff's pedigree to UPenn to be included in their research project, as well as samples of both urine and blood from as many direct relatives as possible.

I'd like to support DNA research for Cystinuria in Mastiffs, where should I send my donations? If you would like to help, you can make a tax deductible donation by writing a check to the MCOA Charitable Health Trust Mail the check to: MCOA Charitable Health Trust C/O Anne Heyob, Treasurer 1345 Murphy Hill Road, Lot 182 Langston, AL 35755 Or you may make donations electronically through the  MCOA Charitable Health Trust Online Payment and Donation Center.   Make check payable to CHF DAF (Canine Health Foundation Donor Advised Fund) and write "Cystinuria" in the notes. Donations and memorials will be published in the MCOA Journal.

Which Mastiffs should be tested for Cystinuria? All Mastiffs should be checked for Cystinuria. It is of particular importance to test the following animals: Mastiffs with suspicious clinical signs. Examples: difficulty or inability to urinate, blood in the urine, crystals or calculi in the bladder, urethra or kidney. Relatives of known cystinuric dogs. All Mastiffs used for breeding. All Mastiff puppies age 4 weeks and older.

What benefits are there in testing my Mastiffs for Cystinuria? Being able to make a positive Cystinuria diagnosis has many benefits: A specific diagnosis can be reached in dogs with suspicious signs. Asymptomatic Mastiffs can be diagnosed with Cystinuria. Mastiffs with Cystinuria can be appropriately managed. Cystinuric Mastiffs can be taken out of the breeding program, thereby eliminating this problem at some point in the future. Affected puppies can be placed on a spay/neuter contract and given special feeding instructions with the new family fully aware of the ramifications of this disease. The screening of all Mastiffs provides valuable information on the prevalence of Cystinuria in this breed and will eventually help to improve the health of the Mastiff breed.

What should I do to prepare my Mastiff for the Cystinuria test? Ideally, the Mastiff should be on a steady diet for at least 30 days prior to collecting urine for the Cystinuria test. The Mastiff should also eat approximately 2-4 hours before collecting the urine in order to get the most accurate reading.

Can I collect urine from my bitch for Cystinuria testing when she's in heat? Yes. You can collect urine for Cystinuria testing while your bitch is in heat. Just add a note to the submission form explaining that there is blood in the urine because the sample was taken from the bitch during her heat cycle. Why should we send our urine samples to UPenn? UPenn is the only facility that is currently trying to find the DNA marker for Cystinuria in Mastiffs. Being able to find the increased levels of cystine in the urine can aid in diagnosing the disease before the Mastiff shows clinical symptoms of Cystinuria. Additionally, you will be helping UPenn to help the MCOA eliminate this problem from the breed, so that future generations will be free of this disease.

Are the sire and dam of affected Mastiffs affected too? The mode of inheritance in Mastiffs has not been determined. Each breed inherits genes differently. In humans and Newfoundland dogs, Cystinuria is inherited as an autosomal recessive trait. This means that the parents of affected cystinuric dogs are either carriers (one mutant gene) or affected (two mutant genes). If this is a dominant gene, only one of the parents would have to be affected with Cystinuria. We are getting close to finding the mode of inheritance, but we need more data.

Are littermates usually affected? Once again, this depends on the mode of inheritance in the Mastiff breed. Littermates of any affected dog should certainly be tested, as should parents and any offspring. My Mastiff's Cystinuria test came back inconclusive.

Do I have to pay to re-test? Yes. UPenn charges to re-test.

Do I need to submit a blood sample to UPenn with my Mastiff's urine sample? No. You only need to submit blood samples if your Mastiff or a parent, offspring or sibling of your Mastiff tests positive for Cystinuria.

Why does UPenn want blood from Mastiffs that were tested positive for Cystinuria and from their relatives? UPenn needs this blood for their research in finding the mutant gene or genes that cause Cystinuria in Mastiffs. Once they are able to do this, they can then begin to create a DNA test for Cystinuria in Mastiffs that can determine if a Mastiff is affected, a carrier or clear of the disease. UPenn has already done this for the Newfoundland Breed.

What does it cost to submit blood to UPenn for Cystinuria Research in Mastiffs? UPenn doesn't charge a fee for blood samples submitted from affected Mastiffs and their relatives. This is a very involved process and the testing is expensive to run. The cost is paid through fundraising by the Cystinuria Subcommittee and the Canine Health Foundation grant. You or your veterinarian must include a letter with the blood samples explaining any information on the diagnosis of Cystinuria (e.g., stone analysis). Please label each blood sample for identification purposes. UPenn would also like you to include the Cystinuria submission form and a pedigree, when possible.

My Mastiff's Cystinuria test came back positive. What should I do? To be absolutely sure, you should run another test and submit samples on as many relatives of this dog as is humanly possible, especially males. Call your breeder and gently explain the situation. Give the diagnosis time to digest in the breeder's mind before making any decisions that may affect your breeder. Once the diagnosis is confirmed, you should alkalinize the Mastiff's urine as much as possible. You may want to have your water checked for acidity levels. If it is highly acidic, consider adding baking soda to your dog's drinking water. It has been thought that if you keep the protein down and eliminate foods high in cystine, such as poultry it may help but this has not been proven.

What treatments are available for Mastiffs with Cystinuria? Many cystinuric dogs will remain symptom-free for years, possibly their entire lives and never develop cystine crystals and stones. If they do develop stones, there is a possibility that they might not become blocked by them, allowing them to go unnoticed. On the other hand, many cystinuric dogs will develop cystine crystals and stones that will block their urinary tract causing pain and infection. We encourage you to hope for the best and be prepared for the worst. It is also wise to use all the precautions that are available for your cystinuric Mastiff. If your Mastiff's urinary tract becomes blocked (common in males) the veterinarian will need to remove the urine from the bladder by either cystocentesis or by catheterization. The veterinarian may then be able to clear the urinary tract by flushing out the crystals with a urinary catheter. Usually, flushing only deposits the crystals back into the bladder where they can again move into a position where the urethra becomes blocked. The dog and owner are fortunate whenever it's possible for the vet to back-flush the stones into the bladder so that they can be removed surgically. Most vets and owners do not allow the same stones to create another blockage, since there is no means of eliminating them once they have formed. There are surgical procedures that redirect the urine flow so that the crystals can be passed more easily. A board certified veterinary surgeon is usually recommended to perform a scrotal urethrostomy. This procedure creates a "new" urethra in dogs that is similar to that of a bitch's. It is shorter, wider and straighter, enabling future stones to pass as easily as they do in bitches. The scrotal urethrostomy is the ONLY option when the stones blocking the dog's urethra cannot be back-flushed into the bladder for surgical removal. This does happen at times due to irritation of the soft tissue surrounding the stones, which further blocks the flow of urine. Your veterinarian can call Dr. Melniczek, VMD directly if he/she would like to discuss an individual case and the options of its treatment.

Are there any drugs available to prevent my cystinuric Mastiff from developing cystine crystals and stones? There is a drug called Thiola that is being used to treat humans with Cystinuria. It can be prescribed for cystinuric dogs. This medication is hard to obtain and very expensive. To treat an adult Mastiff weighing 150-200 pounds with this medication, it costs approximately $450-500 per month. The dosage is based on weight, so larger dogs will cost substantially more to treat. Again, this medication is very difficult to obtain at this point in time in the USA, even for human patients, so it might not even be available initially or consistently.

My Mastiff has developed cystine stones in his bladder and possibly one of his kidneys. What should I do? The stones will need to be surgically removed. As far as the kidney is concerned, your veterinarian will have to evaluate the extent of the damage before recommending further treatment or to determine if the kidney will need to be removed.

Can a nonsurgical procedure eradicate the cystine stones? No. Cystine stones are too soft to be blasted by ultrasound or other procedures. Surgery is required to remove stones and grit.

What type of diet should my Mastiff eat if s/he has Cystinuria? Although giving cystinuric dogs a restricted diet has not been proven to prevent the formation of stones, you may want to avoid poultry and eggs, which are very high in methionine, which is the precursor to cystine. If your Mastiff is prone to cystine stones, avoid diets/dog food based on poultry, including those that use poultry fat or eggs as their main source of fat. You may also want to keep the protein level down. Another good tip is to add a couple of teaspoons of baking soda to your Mastiff's food or drinking water to provide a buffer and to reduce the acidity levels. Do NOT add vitamin C, vinegar, or other acidifiers. If you feel that you must give vitamin C, use Ester C since it is PH neutral. The nutritionist at UPenn, however, strongly advises against any form of vitamin C supplementation. Meat raises acidity levels, so feed it mixed with vegetables, etc., at each meal to produce a balanced diet. As previously mentioned, you may also want to have your water checked. If it's highly acidic, consider adding baking soda to your dog's drinking water, as well.

Are there any cures for Mastiffs with Cystinuria? No, nothing has been proven to cure Cystinuria. Even if a dog is on an alkaline diet low in cystine and is on Thiola, he/she may still have continued problems. There will be no cures, just methods to reduce the risk of reblockage.