X-Linked Hypohidrotic Ectodermal Dysplasia in Crossbred Beef Cattle Due to a Large Deletion in EDA

Abstract

X-linked hypohidrotic ectodermal dysplasia-1 (ECTD1) in people results in a spectrum of abnormalities, most importantly hypotrichosis, anodontia/oligodontia, and absent or defective ectodermally derived glands. Five Red Angus-Simmental calves born over a 6-year period demonstrated severe hypotrichosis and were diagnosed as affected with ECTD1-like syndrome. Two died of severe pneumonia within a week of birth. The skin of three affected calves revealed a predominance of histologically unremarkable small-caliber hair follicles. Larger follicles (>50 µm) containing medullated hairs (including guard and tactile hairs) were largely restricted to the muzzle, chin, tail, eyelids, tragus and distal portions of the limbs and tail. The mean histological density of hair follicles in flank skin of two affected calves was slightly greater than that in two unaffected calves. One affected calf was examined postmortem at 10 days of age to better characterize systemic lesions. Nasolabial, intranasal and tracheobronchial mucosal glands were absent, whereas olfactory glands were unaffected. Mandibular incisor teeth were absent. Premolar teeth were unerupted and widely spaced. Other than oligodontia, histological changes in teeth were modest, featuring multifocal disorganization of ameloblasts, new bone formation in dental alveoli, and small aggregates of osteodentin and cementum at the margins of the enamel organ. A 52,780 base pair deletion spanning six out of eight coding exons of EDA and all of AWAT2 was identified. Partial deletion of the EDA gene is the presumed basis for the reported X-chromosomal recessive inherited genodermatosis.

A Nonsense Variant in Hephaestin Like 1 (HEPHL1) Is Responsible for Congenital Hypotrichosis in Belted Galloway Cattle

“…Particular clinical examination of the cardiovascular, respiratory, genitourinary, musculoskeletal, and nervous systems showed no abnormalities. Moreover, no abnormalities in dentition were noticed as previously seen in cattle affected by ectodermal dysplasia characterized by sparse hair and abnormal teeth [ 37 ].…”

A KRT71 Loss-of-Function Variant Results in Inner Root Sheath Dysplasia and Recessive Congenital Hypotrichosis of Hereford Cattle

“…Particularly, the clinical examination of the cardiovascular, respiratory, urinary, musculoskeletal, and nervous systems showed no abnormalities. Moreover, no abnormalities in dentition were noticed as previously seen in cattle affected by ectodermal dysplasia, which is characterized by sparse hair and abnormal teeth [ 44 ].…”

The genome of tropically adapted Brahman cattle (Bos taurus indicus) reveals novel genome variation in production animals

“…Currently structural variants are not used extensively for phenotypic prediction of quantitative traits in livestock, however the ability to characterise and genotype known structural variants may mean that the phenotypic variation that they induce can be captured by genotyping them using imputation from SNP arrays in the future. Long read data in cattle has already been used to identify economically important traits in cattle such as the poll (hornless) mutation [11], coat color patterns (under review), and deleterious mutations [12].…”