The OptiGen/Antagene FN test is a DNA-based test that accurately diagnoses a fatal kidney disease that occurs in Cocker Spaniels. The test also detects CARRIERS of this disease and clears dogs that are genetically NORMAL. Carriers have the potential to pass the disease onto their offspring and should therefore only be mated to CLEAR dogs to avoid the risk of producing affected puppies.

FN disease is a juvenile-onset fatal kidney (renal) failure recognized in cocker spaniels worldwide for more than 50 years. The renal disease caused by FN invariably is progressive and ultimately fatal; however, the rate of disease progression observed in affected dogs is more rapid in some individuals than in others.

Cockers with FN typically develop chronic renal failure between 6 months and 2 years of age, with eventual and sometimes rapid destruction of both kidneys. The early clinical signs are the same as those associated with chronic renal failure due to any other cause. These include excessive water consumption, excessive urine volume, reduced growth rate or weight loss, poor quality hair coat, reduced appetite, and vomiting. Persistent high levels of protein in the urine of a young cocker spaniel most often proves to be due to FN.

Early in the disease course, a diagnosis can be difficult. Definitive clinical diagnosis can require examination of kidney tissue after death. The FN genetic test solves this problem immediately since presence of the FN gene mutation is accomplished by testing a DNA sample. This result gives the owner immediate diagnostic information and aides in making decisions for the affected dog and for breeding strategies.

Familial Nephropathy (FN) has been referred to in several ways: kidney failure, fatal renal disease, juvenile nephropathy, renal cortical hypoplasia, hereditary nephritis (HN), Autosomal Hereditary Recessive Nephropathy (AHRN) in canines. The disease is also found in humans and is referred to as Alport Syndrome.

FN is inherited in an Autosomal recessive pattern in the cocker spaniel. This means the gene mutation responsible for FN is located on an Autosome (that is, a chromosome that is not a sex chromosome) and FN disease results when the gene mutation is passed to the offspring by both the mother and the father.

Late in 2006, a new DNA test for FN (Familial Nephropathy) was developed by Dr. Lee's and his team at the A and M University in America.

FN is inherited as a recessive trait. This means a disease gene must be inherited from each parent in order to cause disease in an offspring. A carrier has one disease gene and one normal gene, and is termed “heterozygous” for the disease. A normal dog has no disease gene and is termed “homozygous normal” – both copies of the gene are the same. Moreover, a dog with two disease genes is termed “homozygous affected” – both copies of the gene are abnormal.

Because the OptiGen/Antagene FN test is a mutation-based gene test, it accurately and specifically identifies normal dogs, carriers (heterozygous dogs) and affected.

Antagene FN DNA Test Report & OptiGen FN DNA Test Report

For more information about Familial Nephropathy (FN) visit our advice page.

DNA Testing

Two companies are licensed to perform DNA FN testing, OptiGen in the US and Antagene in France.

The OptiGen/Antagene FN test is performed on a small sample of blood from the dog. The option of a cheek swab (Buccal Cheek Swab) has now been added (for commercial reasons), however OptiGen do not recommend this method due to the risk of cross contamination. Our personal feelings are that FN is too devastating a disease to risk getting a false "Clear" due to contaminated DNA and we continue to opt for testing via blood samples.

The DNA from the blood sample is analysed for the gene mutation. The result of the test is a genotype - a fingerprint - that allows separation of dogs into three groups for Cocker Spaniels: Clear, Carrier and Affected.

The option of a cheek swab (Buccal Cheek Swab) has now been added (for commercial reasons), however OptiGen do not recommend this method due to the risk of cross contamination. Our personal feelings are that the risk of cross contamination is too common with DNA samples derived from cheek cells and we personally prefer to continue with testing via blood samples. The risk of cross contamination (from other dogs in our household) is totally removed and we can be sure that the results for our dogs are from their DNA and not their household companions!

The current cost to DNA test a dog is (approximately £10 for the vet to collect the blood sample) and approximately £64 per dog (requesting the test online) to OptiGen for the DNA test.

For an explanation of Autosomal inheritance visit this page.

Please note, the above expected results are based on Mendelian inheritance and the percentages are based on probability, unless the same two parents produce 100 offspring together (probably impossible!!) the difference between expected outcomes and actual results can vary hugely due to the small sample size i.e. a litter containing 6 pups as opposed to 100 puppies!

If you mate, a "clear" to a "carrier" the expected ratio of "clear" to "carrier" offspring is 50/50, however it is possible that the entire litter could be "carriers"! Mate the same parents again and the next litter could be 25% "clear" and 75% "carriers,” mate the parents again and the entire litter could be "clear"! The inheritance of genes is a random process and in a small litter, all could be "carriers" or all could be "clear" (when mating "clear" to "carrier").

To see Powerscourt FN test results please visit our health testing page.