X-linked Hypohidrotic Ectodermal Dysplasia/Anhidrotic Ectodermal Dysplasia (XHED) in German Shepherd Dogs

Quick Summary

X-linked hypohidrotic ectodermal dysplasia is an inherited disorder that affects tissues derived from the ectoderm and causes abnormal development of the skin, hair, nails, teeth, and exocrine glands.

Phenotype: Affected pups are born lacking hair on the forehead and back near the tail. Pups have a high frequency of eye infections prior to opening. Both teeth and secondary hair are either absent or abnormal. The mechanism for clearing matter from the respiratory tract (mucociliary clearance) is diminished, resulting in an increased susceptibility to pulmonary infections. Clinically, a lack of glands in affected dogs has been noted, including bronchial, tracheal, esophageal, and sweat glands.

Mode of Inheritance: X-linked recessive

Alleles: N = Normal/Unaffected, XHEDgs = X-linked hypohidrotic ectodermal dysplasia (German Shepherd variant)

Breeds appropriate for testing: German Shepherd Dog

Explanation of Results:

Males only have one X chromosome whereas females have two, therefore possible genotypes will differ by sex.

  • Female dogs with N/N genoytpe and male dogs with N genotype will not have XHED, and cannot transmit this variant to their offspring.
  • Female dogs with N/XHEDgs genotype will not have XHED, but are carriers. If a carrier female is bred to a normal male, all female puppies will be normal but 50% of them will be carriers. Among male puppies from this type of cross, 50% will be normal and 50% will be affected by XHED.
  • Female dogs with XHEDgs/XHEDgs genotype and male dogs with XHEDgs genotype will have XHED. 

Results of this test can be submitted to the OFA (Orthopedic Foundation for Animals)

Price

$50 one test per animal
$30 as additional test (same animal)

Panels Available
Additional Details

X-linked hypohidrotic ectodermal dysplasia (XHED) is an inherited disorder that has been reported in several breeds and mixed-breed dogs. Affected pups are born lacking hair on the forehead and back near the tail. Pups have a high frequency of eye infections prior to opening. Both teeth and secondary hair are either absent or abnormal. The mechanism for clearing matter from the respiratory tract (mucociliary clearance) is diminished, resulting in an increased susceptibility to pulmonary infections. Clinically, a lack of glands in affected dogs has been noted, including bronchial, tracheal, esophageal and sweat glands.

Except for the German Shepherd Dog, the molecular basis of this defect in different breeds is unknown and likely results from different mutations. In German Shepherd Dogs, XHED deficiency results from a c.910-1G>A (reported as XHEDgs) mutation in the intron 8 splice acceptor site of ectodysplasin A (EDA) gene resulting in abnormal protein production. EDA is involved in the morphogenesis of hair follicles and tooth buds. The disease is inherited in an X-linked recessive fashion. Females with two copies of the affected allele will show disease. Clinical signs are absent in females with one normal and one affected gene (carriers). Males have only one X chromosome. If the inherited allele is affected, males will show disease. If the inherited allele is normal, the dog does not have the disease.

Testing for the German Shepherd form of XHED assists veterinarians with diagnosis of XHED and helps breeders identify carrier females among breeding stock to avoid mating pairs that can produce affected dogs. When a carrier female is bred to a normal male, all female puppies will be normal but 50% of them will be carriers. Among male puppies from this cross, 50% will be normal and 50% will be affected.

Turnaround Time
5-10 business days

Species

Dog

Type of Test

Results Reported As
Test Result X-linked Hypohidrotic Ectodermal Dysplasia

N/N

Normal female. No copies of the XHEDgs mutations.

N/XHEDgs

Carrier female. 1 copy of the XHEDgs mutation.

XHEDgs/XHEDgs

Affected female. 2 copies of the XHEDgs mutation.

N

Normal male. No copies of the XHEDgs mutations.

XHEDgs

Affected male. 1 copy of the XHEDgs mutation.

References

Casal, M.L., Scheidt, J.L., Rhodes, J.L., Henthorn, P.S., & Werner, P. (2005). Mutation identification in a canine model of X-linked ectodermal dysplasia. Mammalian Genome, 16(7), 524-531. doi: 10.1007/s00335-004-2463-4

Casal, M.L., Mauldin, E.A., Ryan, S., Scheidt, J.L., Kennedy, J., Moore, P.F., & Felsburg, P.J. (2005). Frequent respiratory tract infections in the canine model of X-linked ectodermal dysplasia are not caused by an immune deficiency. Veterinary Immunology and Immunopathology, 107, 95-104. doi: 10.1016/j.vetimm.2005.04.005