A large deletion encompassing exon 2 of the ectodysplasin A (EDA) gene in a British blue crossbred calf with hypohidrotic ectodermal dysplasia.

The clinicopathological and genetic findings were consistent with a case of X-linked HED. A very similar EDA deletion has been previously reported in a family of Holstein cattle with HED. The newly identified hemizygous EDA loss-of-function variant is certainly pathogenic and therefore is the genetic cause for the observed phenotype. This case report provides an additional example of the potential of WGS-based precise diagnostics in livestock species such as cattle to increase the diagnostic yield in rare diseases.