Barbara Gandolfi; Claire Rusbridge; Richard Malik; Leslie A. Lyons
The health of the Burmese breed is endangered by several diseases, such as hypokalemia, Burmese craniofacial defect, flat-chested kittens, an acute teething disorder, diabetes mellitus, and feline orofacial pain syndrome (FOPS). FOPS is characterized by an episodic, typically unilateral discomfort with variable pain-free intervals. In many patients, discomfort is triggered by movements of the mouth such as eating, drinking, or grooming. Affected cats are most commonly presented with exaggerated licking and chewing movements and pawing at the mouth. More severe cases develop self-mutilation of tongue, lips and buccal mucosa. Due to the severity of the lesions, many patients display anorexia. The syndrome is often recurrent and with time may become unremitting, with up to 10% of the cases being euthanized as a consequence of the condition. This condition is seen in a variety of feline populations, although Burmese cats make up the great majority of cases, suggesting a genetic basis for the syndrome. A genome-wide case-control association study that aimed to localize the orofacial pain syndrome (FOPS) using the Illumina Infinium Feline 63K iSelect DNA array was performed on 24 cases and 50 healthy controls. The study resulted in the identification of a locus on cat chromosome C1 associated with FOPS. Preliminary data suggest an association on cat chromosome C1, within the low-density lipoprotein receptor-related protein 1 gene (LRP1). The protein expressed in the central nervous system has been implicated in other pain syndromes, and recent studies demonstrate that the gene is involved in migraine without aura. The length of the human transcript is 14,897 bp translated into 4544 amino acids; the gene contains 89 coding exons and is one of the largest genes in the human genome. Sequencing of the feline gene revealed several polymorphisms under consideration.