Primary Lens Luxation - PLL

 

Overview

Primary Lens Luxation (PLL) is the displacement of the lens within the eye of an affected dog. It occurs when the fibres that normally suspend the lens degenerate, causing the lens to detach. This disorder commonly occurs in both eyes of an affected dog.

PLL can result in glaucoma if the displaced lens falls forward causing an accumulation of fluid and an increase in pressure in the eye. This can cause irreversible blindness if left untreated.

Severity - 5

PLL has a very high degree of severity (5). It may cause a severe decrease in the quality of life for an affected dog if left untreated.

Symptoms

PLL typically arises during middle age. Affected dogs may show signs of weakening fibres in the eye before the lens fully detaches. This can be seen as the lens wobbling when the dog moves its head.

This condition can be managed if detected early. Regular eye checks by a veterinary opthamologist are critical in the early detection of PLL.

Genetic Testing

Animal Network provides a DNA test that determines a dog's genetic predisposition to PLL.

PLL is autosomal recessive. A direct gene test can determine whether a dog is clear, a carrier or affected. A recessive phenotype (trait or disease) requires two copies of the causative gene variant for the phenotype to be expressed.

If both parents have two copies of the recessive gene variant, then 100% of all offspring will show the phenotype. If one parent has two copies of the recessive gene variant and the other parent is a carrier with a single copy, then 50% of all offspring will show the phenotype and 50% will be carriers. If both parents are carriers of the recessive gene variant then 25% of all offspring will show the phenotype, 50% will be carriers and 25% will be clear. If one parent is a carrier and the other is clear then 50% of offspring will be carriers and 50% will be clear.

Due to the probability of genetic inheritance, the actual outcome of matings may vary from expected ratios, eg two carriers may produce all clear or all affected.

For an explanation of possible genetic status of offspring please refer to our Fact Sheet on Breeding Strategies. ORDER A TEST

Breeds Affected

Chinese Crested
Australian Cattle Dog
Jack Russell Terrier
Miniature Bull Terrier
Sealyham Terrier
Tenterfield Terrier
Tibetan Terrier
Welsh Terrier
Parson Russell Terrier


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