Explanation of Required Tests

As of December, 2020, Shetland Sheepdogs ranked 166th of 198 breeds of dogs evaluated for hip dysplasia by the Orthopedic Foundation for Animals (OFA) www.ofa.org. Of 24,759 Shelties evaluated, 4.7% were dysplastic. OFA certification or PennHIP evaluation of the hips (x-ray examination) is on the required list for the CHIC program because hip dysplasia can be a crippling disorder, and one affected influential dog used in breeding programs could increase the incidence in Shelties. OFA hip evaluation results are automatically included in the OFA database with no extra charge. More information can be obtained by clicking on the following link https://www.ofa.org/diseases/hip-dysplasia.

Eye abnormalities can occur at any age. Ophthalmic examination can detect a variety of congenital abnormalities, including Progressive Retinal Atrophy (PRA) and Collie eye anomaly (CEA), which also occurs in Shelties. The merling gene may make it difficult to detect mild cases of CEA by ophthalmic examination because merling is normally associated with less pigmentation of the eyegrounds (back of the eye). Also, the CEA lesions (chorioretinal hypoplasia) in some mildly affected dogs may be partially masked as the eye matures so may be missed at 8-10 weeks of age or later. Thus examination at an early age, about 5-8 weeks of age, is recommended. Because the onset of other eye diseases (such as cataracts and retinal degeneration) can occur at any age, dogs should be reexamined periodically. Ideally, each dog should be examined within the preceding 12 mos. of being bred. According to the link above, the likelihood of a genetic problem showing up after age 9 years is low. The test is an eye examination performed by a board certified veterinary ophthalmologist.  See https://www.ofa.org/diseases/eye-certification for more information.

OFA Eye Registry Report

Descriptions of ocular disorders in Shetland Sheepdogs and statistics can be found at https://www.ofa.org/diseases/eye-certification/blue-book . All abnormal findings are listed, and no dog names are included in these reports. Dogs receiving more than one examination in a given year are not listed more than once. The report summarizes eye examination findings from 1991 through the end of the most current complete year.

Progressive retinal atrophy (PRA) is progressive retinal degeneration that causes visual impairment and eventual blindness. There are many different forms of PRA. It has been diagnosed in over 100 breeds, and at least 22 mutations have been found in 50 or more breeds. The age of onset and rate of progression varies. Night blindness is often the first sign of PRA noticed by owners.

In 2020, British researchers identified a mutation that causes a form of PRA in Shetland Sheepdogs in the UK called BBS2-PRA [1,2].  Along with PRA, affected dogs have physical characteristics that include an upturned nose, an unusual coat texture which is wavy, and dental defects (Figure 1).  The condition is comparable to a syndrome in humans called Bardet-Biedl syndrome.  Blindness occurs from 5-10 years of age.  The condition is autosomal recessive meaning that dogs with 1 copy of the mutation (carriers) are normal, but dogs with 2 copies of the mutation (homozygous) will become blind with age.

Figure 1 – Sheltie with Bardet Biedl syndrome. Image from reference #2.

Most forms of PRA appear to be uncommon in American Shelties; however, the BBS2 mutation was found in a small number of American Shelties after one DNA testing laboratory added the test to its Sheltie panel in 2020.  In 2025, data from 2 DNA testing laboratories revealed that of 2,110 Shelties tested for the PRA-BBS2 mutation, 4.6% (97 dogs) were carriers and 3 dogs had 2 copies of the mutation and expected to become blind with age.

Because dogs with 2 copies of the mutation will become blind, the PRA-BBS2 test was added to the Required List of tests for CHIC status in 2025.  Sheltie breeders should know the DNA status of dogs before breeding.  Dogs with one copy of the mutation can be bred, but only to ones tested clear to prevent production of affected puppies.