DNA based diagnosis of rare diseases in veterinary medicine: A 4.4 kb deletion of ITGB4 causes epidermolysis bullosa in Charolais cattle. RM47

A single full-term stillborn purebred Charolais calf showed severe skin lesions. These findings exactly match the gross description given by previous reports on epitheliogenisis imperfecta and epidermolysis bullosa (EB) in cattle. Histological examination is consistent with junctional epidermolysis bullosa (JEB). Genetic analysis revealed a private ITGB4 loss of function mutation: the affected calf was homozygous for a 4.4 kb deletion encompassing exon 17 to 22, and both parents carried a single copy of the deletion indicating recessive inheritance. The homozygous mutant genotype didn’t occur in healthy controls of various breeds but some heterozygous carriers were found among Charolais cattle belonging to the affected flock. The mutant allele was absent in a representative sample of unrelated artificial insemination sires of the German Charolais population indicating that the mutation arose recently.