Prevalence of Unilateral and Bilateral Deafness in Border Collies and Association with Phenotype

Abstract

Background: Congenital sensorineural deafness (CSD) occurs in Border Collies, but its prevalence and inheritance are unknown. This study estimated the prevalence of CSD in Border Collies and investigated its association with phenotypic attributes linked to the merle gene, including coat pigmentation and iris color.Hypothesis: Deafness in Border Collies is associated with pigmentation patterns linked to the merle gene. Animals: A total of 2597 Border Collies from the United Kingdom. Methods: A retrospective study of Border Collies tested, during 1994-2002, by using brainstem auditory evoked responses. Associations between deafness and phenotypic attributes were assessed by using generalized logistic regression.Results: The prevalence of CSD in puppies was estimated as 2.8%. The corresponding rates of unilateral and bilateral CSD were 2.3 and 0.5%, respectively. Adjustment for clustering of hearing status by litter reduced the overall prevalence estimate to 1.6%. There was no association between CSD and sex (P 5 .2). Deaf Border Collies had higher rates of merle coat pigmentation, blue iris pigment, and excess white on the head than normal hearing Border Collies (all P , .001). The odds of deafness were increased by a factor of 14 for Border Collies with deaf dams, relative to the odds for dogs with normal dams (P 5 .007), after adjustment for phenotypic attributes.Conclusions and Clinical Importance: Associations between CSD and pigmentation patterns linked to the merle gene were demonstrated for Border Collies. Evidence for an inherited component to CSD in Border Collies supports selective breeding from only tested and normal parents to reduce the prevalence of this disease.

Evaluation of the occurrence of canine congenital sensorineural deafness in puppies of predisposed dog breeds using the brainstem auditory evoked response

“…In total, there were more unilaterally deaf individuals (11.1%) than bilaterally deaf dogs (4.9%). This is in accordance with the results of other studies in which the frequency of unilaterally affected animals was generally higher than that of bilaterally deaf animals (Platt et al, 2006).…”

Brainstem auditory evoked potential testing in Dalmatian dogs in Brazil

“…The suggestions for inheritance of deafness in Dalmatians include a dominant gene with incomplete penetrance, double dominant genes, or multifactorial recessive genes (Strain et al, 1992). Previous studies have identified statistically significant associations between deafness and a blue iris colour and white coat pigmentation (Strain, 2004;Platt et al, 2006). In the present article the occurrence was higher in dogs with one or two blue eyes.…”

Brainstem auditory-evoked potential in Boxer dogs

“…We found unilateral deafness in 1 and bilateral deafness in 2 Boxers. Other studies that have evaluated the incidence of deafness showed a higher incidence of unilateral deafness compared to bilateral deafness in different breeds, such as Border Collies (2.3% unilateral and 0.5% bilateral) (Platt et al 2006), Bull Terriers (9.9% unilateral and 1.1% bilateral) (Strain 2004), Australian cattle dogs (12.2% unilateral and 2.4% bilateral) (Strain 2004), English Setters (12.7% unilateral and 2.4 bilateral) (Strain 1996) and English Cocker Spaniels (7% unilateral and 1.8% bilateral) (Strain 1996). The fact that this report found more bilateral deafness than unilateral, when other published reports, studying other breeds, found a higher prevalence of unilateral than bilateral, is certainly the result of the small sample size.…”

“…The fact that this report found more bilateral deafness than unilateral, when other published reports, studying other breeds, found a higher prevalence of unilateral than bilateral, is certainly the result of the small sample size. Deafness in dogs is frequently associated with altered expression of pigment genes, such as piebald and merle (Strain et al 2009), and several prior studies have identified statistically significant associations between deafness and a blue iris colour and white coat pigmentation (Strain 2004, Platt et al 2006, Famula et al 2007). Since not all dogs with piebald are deaf or have blue eyes, it can be argued that this variable outcome is the consequence of incomplete penetrance of a causative gene, or that one or more additional genes regulate the expression of the pigment gene (Strain 2011a).…”

“…The use of BAEP testing to diagnose congenital sensorineural deafness has been extensively studied in dogs over the past 30 years (Bodenhamer et al 1985, Haagen et al 1989, Kawasaki & Inada 1994, Juraschko et al 2003, Platt et al 2006, Wilson et al 2011. The breeds with the highest prevalence of deafness include the Australian Cattle Dog, Australian Shepherd, Bull Terrier, Catahoula, Dalmatian, English Cocker Spaniel, English Setter and West Highland White Terrier (Strain 1996).…”