Petersen Tanja, Proschowsky Helle Friis, Hardon Tommy, Rasch Søren Nyhuus, Fredholm Merete
Animal Genetics, Department of Veterinary Clinical and Animal Science, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
The Danish Kennel Club, Solrød Strand, Denmark.
Canine Genet Epidemiol. 2015 Aug 2;2:11. doi: 10.1186/s40575-015-0024-7. eCollection 2015.
Canine distichiasis is a well-known cause of ocular irritation and excessive lacrimation (secretion of tears) in the dog. The term distichiasis originates from the Greek words di and stichos meaning two and rows, respectively, and as the name implies, the condition is characterized by an additional row of cilia, which erupts on the eyelid margin. Many purebred dogs are known to be predisposed to the condition, with many affected individuals within the populations. Even though the problem is widespread, the exact mode of inheritance and the heredity has not been studied extensively. However, some degree of genetic influence has been assumed, due to the high incidences within specific breeds. In the present study we have examined a cohort of English Cocker spaniels in Denmark to determine the prevalence and heritability of the disease.
Data from English Cocker spaniels with an ECVO eye examination registered between 2004-2013 were included in the study. The number of dogs examined during this period was 799, and the prevalence of distichiasis within this cohort was estimated at 49.31 % with a gender predisposition that females are more likely to get distichiasis than males. The correlation between the distichiasis status of the parents and their offspring revealed a significant association between the breeding combination of the parents and the occurrence of distichiasis in the offspring (p <0.0001). A relative risk (RR) ranging from 1.3 to 1.8 demonstrates that offspring of two affected parents are more likely to be affected than offspring descending from either one or two unaffected parents. The heritability was estimated to be moderate to high, i.e., 0.22 to 0.51.
The prevalence of distichiasis in English Cocker spaniels from Denmark, examined in 2004-2013 was shown to be extremely high. The relative risk of developing the disease was 1.3 and 1.8 for offspring of one or two affected parents respectively. This together with the moderate to high heritability of the condition indicates that selective breeding could be used to reduce the incidence of distichiasis.
犬双行睫是犬眼部刺激和泪液分泌过多（流泪）的一个常见病因。双行睫这个术语源于希腊语中的“di”和“stichos”，分别意为“二”和“排”，顾名思义，这种病症的特征是在眼睑边缘长出额外一排睫毛。已知许多纯种犬易患此病，种群中有许多患病个体。尽管这个问题很普遍，但确切的遗传模式和遗传情况尚未得到广泛研究。然而，由于特定品种中的高发病率，已假定存在一定程度的遗传影响。在本研究中，我们对丹麦的一群英国可卡犬进行了检查，以确定该疾病的患病率和遗传力。
2004年至2013年间进行欧洲兽医眼科医生委员会（ECVO）眼部检查的英国可卡犬的数据被纳入研究。在此期间检查的犬只数量为799只，该队列中双行睫的患病率估计为49.31%，存在性别易感性，即雌性比雄性更易患双行睫。父母与后代双行睫状况之间的相关性显示，父母的繁殖组合与后代双行睫的发生之间存在显著关联（p<0.0001）。相对风险（RR）在1.3至1.8之间，表明两个患病父母的后代比一方或双方未患病父母的后代更易患病。遗传力估计为中度至高，即0.22至0.51。
2004年至2013年间检查的丹麦英国可卡犬中双行睫的患病率极高。患病父母一方或双方的后代患该病的相对风险分别为1.3和1.8。这与该病中度至高的遗传力表明，可通过选择性育种来降低双行睫的发病率。
