WHAT IS PRA

PRA is a condition of the eye that causes blindness which becomes apparent usually from about the age of 4 onwards. There is no cure or treatment. Every dog has two copies of the gene inherited from the parents, one from the mother and one from the father. If the dog inherits two damaged genes, PRA will result, but if only one is damaged the dog will become a carrier, able to pass the gene on but with no sign of the disease itself - a "silent" carrier. On average when two carriers are mated together 25% of the off spring will be affected by PRA, another 50% will be carriers able to pass the gene on, and 25% will be clear. To date we have only had 13 officially recognised cases in about 30 years in the UK.

THE PRA FUND

We are hoping to develop a linked marker DNA test which is 98-99% accurate which will provide breeders with the information as to whether a dog is clear, a carrier or a PRA case. This only needs to be done once and can be done at any age. Breeders can then breed a clear to a clear or a carrier to a clear dog thereby ensuring that all the puppies are either clear or a carrier. The use of carriers in our programme in the foreseeable future should continue as we do not want to get puppies which are PRA clear but are not good examples of the breed.

The test will not be limited to the United Kingdom and once it is established scientists will be able to test a small amount of an individual dog's DNA prepared from either cells taken from the inside of a dog's mouth or a small sample of its blood. The Animal Health Trust is a charitable organisation and their intention is to keep the eventual cost of testing down to the minimum so that it will be within the reach of all breeders.

Four of us in England have set up a Fund to raise money to obtain a linker marker gene test. The amount of money required is huge but we are raising funds and are hopeful that our Kennel Club will support the venture. We have approached the Animal Health Trust which is known throughout the world and , they hope that a linked marker test for PRA in Tibetan Spaniels should be available by the end of 2002.

We now have three quarters of the money in the bank or in pledges and we have approximately 200 blood samples in store. We are most grateful to people and clubs who have donated money and to Finland, a breeder in the USA and breeders in England who have supplied the blood.

It looks as though we will progress quite speedily. This is good news for the future of Tibetan Spaniels and I am sure will be gratefully received by all who love the breed.

Maureen Sharp March 2002

PEDIGREES OF PRA CASES

Pedigrees of PRA cases is given on the International Working Party for Tibetan Spaniels web site on
http://home.swipnet.se/~w-34940/