Distichiasis in the Icelandic Sheepdog

Abstract

Distichiasis is a disorder of the eyelid, which is seen in many different dog breeds. Recent numbers show a prevalence of 9 percent of distichiasis in the Dutch Icelandic Sheepdog population. Therefore an inherited background is suspected. The current method of diagnosing this disorder often gives a false negative result, which makes it unreliable for the selection of breeding dogs. In order to eliminate this disorder, a more reliable diagnosing method, like a DNA test, is desirable. Mutations in the human FOXC2 and the TWIST2 gene cause disorders that most commonly are presented with distichiasis: the lymphoedema-distichiasis syndrome and the Setleis syndrome respectively. Mutations in the murine foxc2 and twist2 gene show a similar phenotype in mice. The fact that these genes are present in dogs makes it interesting to analyze them, in order to hopefully find the genetic anomaly that causes distichiasis. DNA from sixteen Dutch Icelandic Sheepdogs (eight dogs diagnosed with distichiasis and eight negative control dogs) is collected and the TWIST2 and the FOXC2 genes are multiplied using PCR. The DNA is sequenced and DNA from the control dogs will be compared with DNA from the dogs diagnosed with distichiasis. Due to logistic difficulties no DNA-sequence results have been produced during the time span of this research. Since the DNA-sequencing has not been completed, more research needs to be done in order to conclude whether or not the genes are involved in distichiasis in Icelandic Sheepdogs