Disorder - Progressive Retinal Atrophy (PRA) (X-linked)

Organ Systems Involved
Nervous/sensory

Alternative Names
Congenital Night Blindness
Pigment Epithelial Dystrophy
Primary Retinal Degeneration
Rod-cone Dysplasia
Rod Dysplasia
Rod-cone Degeneration

Brief Description

A condition where the nerve cells and blood vessels of the retina (the layer at the back of the eye that responds to light, collects messages and passes them on to the brain) degenerate.

Presenting Signs

Progressive Retinal Atrophy is the most common disease of the retina in dogs. It has been divided into two categories: Generalised PRA and Central PRA, based on the symptoms. The age at which the degeneration begins varies between breeds and individual dogs. In both instances, the receptor (nerve) cells lining the retina begin to degenerate and the blood vessels feeding the retina become smaller, so less nutrients reach the eye. An early sign of Generalised PRA is night blindness, which progresses until day vision is affected, and eventually ends in total blindness. The disease first attacks the rod cells (light sensitive cells), so night vision is affected. The dog is shy and has poor vision at dusk and at night, or in dimly lit places. It also moves with caution and has a tendency to bump into objects. Other symptoms include the loss of peripheral vision, resulting in 'tunnel vision' in which the dog can only see objects directly in front of it. Also, the pupils of the dog will be dilated, to allow more light into the eye, and the retina is extremely reflective when the dog faces lights at night. Central PRA is different as peripheral vision is unaffected for many years. However, the central field of vision of the dog is impaired. Night blindness is not so commonly seen. The dog can still see moving objects up to a point where the disease is very advanced, but it will collide with stationary objects. In later stages of the disease, cataracts may form in the eye.

Groups Affected
Gundog
Hound
Non Sporting
Terrier
Toy
Utility
Working dog


Breeds Affected
Afghan hound
Airedale terrier
Akita
Alaskan malamute
American cocker spaniel
American Staffordshire terrier
Australian cattle dog
Australian kelpie
Australian shepherd
Australian silky terrier
Australian terrier
Basenji
Basset hound
Beagle
Bearded collie
Bedlington terrier
Belgian Shepherd Dog (Laekenois and Groenendael)
Belgian Shepherd Dog (Malinois)
Belgian Shepherd Dog (Tervueren)
Bernese mountain dog
Border terrier
Borzoi
Boston terrier
Boxer
Briard
Brittany
Bullmastiff
Cairn terrier
Cavalier King Charles spaniel
Chesapeake Bay retriever
Chow chow
Cocker spaniel
Collie (Rough and Smooth)
Curly-coated retriever
Dachshund (long, smooth and wire haired)
Dachshund (miniature - long, smooth and wire-haired)
Dalmatian
Dobermann
English pointer
English setter
English springer spaniel
English Toy terrier (Black and Tan)
Field spaniel
Flat-coated retriever
Fox terrier (Wire)
German shepherd dog
German short-haired pointer
Golden retriever
Gordon setter
Great Dane
Greyhound
Griffon Bruxellois
Havanese
Hungarian vizsla
Irish setter
Irish terrier
Irish water spaniel
Italian greyhound
Japanese chin
Keeshond
Kerry blue terrier
Labrador retriever
Lhasa Apso
Maltese
Manchester terrier
Mastiff
Miniature pinscher
Neapolitan mastiff
Norwegian elkhound
Nova Scotia duck tolling retriever
Old English sheepdog
Papillon
Pekingese
Pomeranian
Poodle (Miniature)
Poodle (Standard)
Poodle (Toy)
Portuguese water dog
Pug
Puli
Rhodesian ridgeback
Rottweiler
Saluki
Samoyed
Schipperke
Schnauzer (Giant)
Schnauzer (miniature)
Scottish terrier
Sealyham terrier
Shar Pei
Shetland sheepdog
Shih Tzu
Siberian husky
Soft-coated wheaten terrier
Tibetan terrier
Weimaraner
Welsh Corgi (Cardigan)
Welsh Corgi (Pembroke)
Welsh springer spaniel
Whippet
Yorkshire terrier


Related Disorders

Cataracts
Glaucoma
Hemeralopia

PubMed References
Progressive Retinal Atrophy (PRA) (X-linked)

Further Reference Material [OMIA Number]
831


Contributor
Xiang Jie Khor