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Eye Problems
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Are Siberian Huskies prone to eye problems?
Of the three major eye diseases of the Siberian Husky, hereditary cataracts are the most common, followed by corneal dystrophy, and progressive retinal atrophy. Within the last several years (since 1999 or so) the has been an increase in Siberian Huskies diagnosed with glaucoma, as well.
All of these eye problems are most likely genetically caused. Careful screening of potential breeding pairs has helped reduce the incidence of these problem in the breed, and the current incidence of PRA is relatively low.
Obviously, Siberian owners and breeders should regularly check and clear eyes through CERF prior to embarking on a breeding program.
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What are juvenile cataracts?
According to CERF, the incidence of juvenille cataracts in the breed checked by ACVO veterinarians is around 15-18%. The actual incidence is probably higher as many long time breeders discover the anomaly in young dogs early and never certify them. With a typical juvenille cataract, the dogs vision is not usually substantially affected, and they lead
a full, happy, albeit it neutered, life. However, a more aggressive cataract also exists, which progresses quickly and may cause blindness by 2 to 3 years of age.
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What is corneal dystrophy?
Corneal dystrophy affects the cornea or the outer transparent portion of the eyeball. In most cases, Siberian Huskies with this disorder have an abnormal collection of lipids in the clear cornea of the eye which results in a hazy or crystalline opacity. Ophthalmologists describe the location of the opacity as anterior, mid, or deep stromal. The Siberian Husky is prone to deep stromal dystrophy which involves triglyceride deposits. Annular dystrophy also occurs and appears as a doughnut shaped opacity in the peripheral cornea. Corneal dystrophy is usually seen in young adult dogs and may affect females more than males. Vision is seldom affected and no effective therapy for the condition exists at this time. Recent genetic tests are suggesting that a recessive gene with variant expression transmits this disorder. Some corneal dystrophy is often not present or detectable until age 4 to 6 years, at which time the dog could easily have produced a few litters and perpetuated the problem. This will prove to be a difficult genetic disease to eliminate from the breed.
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What is PRA/CPRA?
Progressive retinal atrophy (PRA) and central progressive retinal atrophy (CPRA) affects the retina, the light-sensitive inner lining of the posterior part of the eyeball. The retina contains two types of specialized cells called rods and cones. The rods are necessary for sight in dim light or night light, and the cones are utilized in in bright light vision. The Siberian Husky has a unique type of PRA that is only found in Siberians and man. This type of PRA is called XLPRA (X Linked PRA) since it is transmitted through the "XX" chromosome of the female. It will cause a loss of night vision followed by a loss of day vision, eventually blindness. The recessive gene for XLPRA is situated on the "X" chromosome of the female. Females who inherit a defective gene on the "X" chromosome from one parent and a normal gene on the other "X" chromosome from the other parent, will not be seriously affected. They will be carriers with very subtle retinal defects and no loss of vision. The male puppy from a carrier dam will receive either a defective gene or a normal gene, depending on what chromosome was copied in the DNA replication. If he has the defective gene, the dog will be affected with PRA since males carry an "XY" chromosome. The disease in males can be devastating with loss of vision as early as 5 months of age.
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What is glaucoma?
Glaucoma causes the animal significant pain and vision loss usually before it is detected by the owner. This disease is still being investigated by the Siberian Husky Club of America to determine it's significance in the breed. They have not yet (as of February 2005) recognized it as a hereditary disease in the Siberian Husky.
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