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

Capuzzello, G., Jacinto, J. G. P., Häfliger, I. M., Chapman, G. E., Soto Martin, S., Viora, L. , Jonsson, N. N. and Drögemüller, C. (2022) A large deletion encompassing exon 2 of the ectodysplasin A (EDA) gene in a British blue crossbred calf with hypohidrotic ectodermal dysplasia. Acta Veterinaria Scandinavica, 64, 23. (doi: 10.1186/s13028-022-00641-2) (PMID:36068608) (PMCID:PMC9446731)

Abstract

Background: Hypohidrotic ectodermal dysplasia (HED) is a congenital syndrome of mammals affecting organs and tissues of ectodermal origin characterized by absence or hypoplasia of hair, teeth, and eccrine glands. The disorder has been reported in several species, including humans, mice, dogs and cattle, associated with variants in genes affecting the ectodysplasin pathway, including the X-linked ectodysplasin A (EDA) gene. Until now, nine pathogenic variants have been found in the bovine EDA gene. Here we report a novel variant in EDA in a crossbreed male Belgian Blue calf with HED, and provide an overview of the phenotypic and allelic heterogeneity of EDA-related forms of HED in cattle. Case presentation: A 45-day-old male crossbreed British Blue calf was referred with congenital hypotrichosis, oligodontia and omphalitis. On histopathological examination of the nasal planum, nasolabial glands and ducts were not observed. The density of hair follicles was low, and they were small, with a predominance of telogen-phase hairs, and some serocellular crusts. The phenotype of the calf resembled that of HED. Whole-genome sequencing (WGS) was performed and revealed a 21,899 base-pair deletion encompassing the coding exon 2 of EDA, predicted to result in an altered transcript and aberrant protein. Conclusions: 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.

• Item Type: Articles
• Additional Information: The study was partially funded by the Swiss National Science Foundation, Grant number 172911, and the University of Glasgow.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Chapman, Gail and Jonsson, Professor Nicholas and Capuzzello, Giovanni and Viora, Dr Lorenzo
• Authors: Capuzzello, G., Jacinto, J. G. P., Häfliger, I. M., Chapman, G. E., Soto Martin, S., Viora, L., Jonsson, N. N., and Drögemüller, C.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Acta Veterinaria Scandinavica
• Publisher: BioMed Central
• ISSN: 1751-0147
• ISSN (Online): 1751-0147
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in Acta Veterinaria Scandinavica 64: 23
• Publisher Policy: Reproduced under a Creative Commons License