Primary Lens Luxation (PLL)

PLL is a well-recognised, painful and blinding inherited eye condition that affects many breeds of dog.

In affected dogs, the zonular fibres which support the lens in the eye, breakdown or disintegrate, causing the lens to fall into the wrong position within the eye. If the lens falls into the anterior chamber of the eye, glaucoma and loss of vision can quickly result.

Clinical signs include reddening of the eye, glaucoma (increased pressure within the eyeball) and loss of vision, which can be detectable at 20 months. Complete lens luxation typically occurs at the age of 3-8 years.

The disease is an inherited condition and is described as an autosomal-recessive condition. This means that a dog must inherit two copies of an abnormal gene (one from its mother and one from its father) before its health is affected. A dog that inherits only one copy of the abnormal gene (from its mother or its father) will have no signs of the disease but will be a carrier and may pass the gene on to any offspring.

Two clear parents can only produce clear puppies – these puppies do not need to be tested as they are ‘clear by parentage’.
A ‘clear’ can be mated to a ‘carrier’ in which case all pups must be tested as they could be “clear” or a “carrier” and should be certificated to confirm their status.

In theory an ‘affected’ could be mated to a clear, although, the club does not endorse the mating of “affected dogs”. ALL pups would be ‘carriers’ and would require a test and a certificate to prove it.

Under no circumstances should anyone breed using two ‘carriers’.

The DNA test to identify a dog’s status as ‘affected’, ‘carrier’ or ‘clear’ was launched in 2009 following collaboration between the MBTC, the Kennel Club and the Animal Health Trust (AHT). This means that the PLL status of all puppies can be determined from the age of 5 weeks.

The PLL DNA test is a once in a lifetime test and all breeding dogs should have evidence of their PLL status as should all puppies.

The MBTC strongly recommends its members DNA test their Miniature Bull Terrier for PLL – a test kit can be obtained from the laboratories below.

Animal Genetics (UK)
Only available for the following breeds:

  • Bull terrier (miniature)
  • Jack Russell Terrier
  • Lancashire Heeler
  • Parsons Russell Terrier
  • Tibetan terrier
  • Welsh terrier

Phone: 01726 247788
Email: Animal Genetics

Laboklin (UK)

Phone: 0161 282 3066
Phone: 01624 679 720
Email: Laboklin

Pet Genetics Lab (UK)

Email: Pet Genetics Lab

Please note that the Animal Health Trust (AHT) closed down on 31 July 2020 and no longer offers this test.
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