Anhidrotic Ectodermal Dysplasia

Other Names: Congenital hypotrichosis, Ectodermal dysplasia, X-linked ectodermal dysplasia, X-linked hypohidrotic ectodermal dysplasia, XHED, XLED
Affected Genes: EDA
Inheritance: X-Linked Recessive
Mutation: Point Mutation

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Common Symptoms

Anhidrotic Ectodermal Dysplasia is an inherited disease affecting German shepherd dogs. This disease most commonly presents at birth. Affected dogs are born with symmetrical hairlessness on the forehead and the area over the lower back. Malformed and/or absent teeth (oligodontia) are also a feature of the disorder. Dogs may also have an inability to sweat (anhidrosis) due to missing or abnormal sweat glands. Tear production can be abnormal and dogs often develop dry eye (keratoconjuncitivitis sicca). Affected dogs are more prone to respiratory infections than other dogs and frequently have chronic nasal discharge. Prognosis for survival to adulthood is good. However, affected dogs should be monitored for signs of respiratory infections (cough, rapid or difficult breathing, and exercise intolerance) as they are fatal in rare cases.


Breed-Specific Information for the German Shepherd Dog

The Mutation of the EDA gene associated with anhidrotic ectodermal dysplasia has been identified in German shepherd dogs, although its overall frequency in this breed is unknown.


Testing Tips

Genetic testing of the EDA gene in German shepherd dogs will reliably determine whether a dog is a genetic Carrier of anhidrotic ectodermal dysplasia. Anhidrotic Ectodermal Dysplasia is inherited in an X-Linked Recessive manner in dogs meaning that female dogs must receive two copies of the mutated gene (one from each parent) to develop the disease while male dogs only require one copy of the mutated gene from the mother in order to develop the disease. Therefore, male dogs more commonly present with symptoms of the disease. Although much less common, carrier female dogs may present with mild symptoms. Each male pup that is born to a female dog known to be a carrier of anhidrotic ectodermal dysplasia has a 50% chance of inheriting the disease. Female dogs that are not carriers of this Mutation have no increased risk of having affected pups. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. German shepherd dogs that are not carriers of the mutation have no increased risk of having affected pups.


There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.


References

  • Casal ML, Lewis JR, Mauldin EA, Tardivel A, Ingold K, Favre M, Paradies F, Demotz S, Gaide O, Schneider P. Significant correction of disease after postnatal administration of recombinant ectodysplasin A in canine X-linked ectodermal dysplasia. Am J Hum Genet. 2007 Nov; 81(5):1050-6. [PubMed: 17924345]
  • Casal ML, Mauldin EA, Ryan S, Scheidt JL, Kennedy J, Moore PF, Felsburg PJ. Vet Immunol Immunopathol. Frequent respiratory tract infections in the canine model of X-linked ectodermal dysplasia are not caused by an immune deficiency. 2005 Aug 15; 107(1-2):95-104. [PubMed: 15946744]
  • Casal ML, Scheidt JL, Rhodes JL, Henthorn PS, Werner P. Mutation identification in a canine model of X-linked ectodermal dysplasia. Mamm Genome. 2005 Jul; 16(7):524-31. [PubMed: 16151697]
  • Kowalczyk C, Dunkel N, Willen L, Casal ML, Mauldin EA, Gaide O, Tardivel A, Badic G, Etter AL, Favre M, Jefferson DM, Headon DJ, Demotz S, Schneider P. J Biol Chem. 2011 Sep 2; 286(35):30769-79. Molecular and therapeutic characterization of anti-ectodysplasin A receptor (EDAR) agonist monoclonal antibodies. [PubMed: 21730053]
  • Lewis JR, Reiter AM, Mauldin EA, Casal ML. Orthod Craniofac Res. 2010 Feb; 13(1):40-7. Dental abnormalities associated with X-linked hypohidrotic ectodermal dysplasia in dogs. [PubMed: 20078794]
  • Mauldin EA, Gaide O, Schneider P, Casal ML. Am J Med Genet A. 2009 Sep; 149A(9):2045-9. Neonatal treatment with recombinant ectodysplasin prevents respiratory disease in dogs with X-linked ectodermal dysplasia. [PubMed: 19533784]
  • Moura E, Cirio SM. Clinical and genetic aspects of X-linked ectodermal dysplasia in the dog -- a review including three new spontaneous cases. Vet Dermatol. 2004 Oct; 15(5):269-77. [PubMed: 15500478]