Disease overview

Cone-Rod Dystrophy 4 is a type of Progressive Retinal Atrophy (PRA). This is an early-onset form of the disease that affects both rod and cones. Rod cells are responsible for vision in low light conditions and for detecting and following movement, while cone cells detect color and adjust brightness, but do not work as well in low light.

Gene name

RPGRIP1

Inheritance

Autosomal recessive

Signs and symptoms

Signs of change in the tapetum, the reflective surface of the eye, may begin as early as 6 months of age. Subsequent symptoms include vision loss in dim light environments and progressive visual deficits, which can lead to complete blindness. The disease can progress rapidly within a few months.

How is it diagnosed

Thorough examination of the eyes and clinical signs. A veterinary ophthalmologic exam can determine if there are changes in the eye that could lead to vision loss. Genetic testing assists veterinarians with diagnosis and helps breeders identify affected and carrier dogs.

Breeds at higher risk

Miniature Long-Haired Dachsund

Citations

Mellersh CS, Boursnell ME, Pettitt L, Ryder EJ, Holmes NG, Grafham D, Forman OP, Sampson J, Barnett KC, Blanton S, Binns MM, Vaudin M. Canine RPGRIP1 mutation establishes cone-rod dystrophy in miniature longhaired dachshunds as a homologue of human Leber congenital amaurosis. Genomics. 2006 Sep;88(3):293-301. doi: 10.1016/j.ygeno.2006.05.004. Epub 2006 Jun 27. PMID: 16806805.

Forman OP, Hitti RJ, Boursnell M, Miyadera K, Sargan D, Mellersh C. Canine genome assembly correction facilitates identification of a MAP9 deletion as a potential age of onset modifier for RPGRIP1-associated canine retinal degeneration. Mamm Genome. 2016 Jun;27(5-6):237-45. doi: 10.1007/s00335-016-9627-x. Epub 2016 Mar 26. PMID: 27017229.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.