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Hypohidrotic ectodermal dysplasia

Reviewed August 2006

What is hypohidrotic ectodermal dysplasia?

Hypohidrotic ectodermal dysplasia is one of about 150 types of ectodermal dysplasia in humans. Before birth, these disorders result in the abnormal development of structures including the skin, hair, nails, teeth, and sweat glands.

Most people with hypohidrotic ectodermal dysplasia have a reduced ability to sweat (hypohidrosis) because they have fewer sweat glands than normal or their sweat glands do not function properly. Sweating is a major way that the body controls its temperature; as sweat evaporates from the skin, it cools the body. An inability to sweat can lead to a dangerously high body temperature (hyperthermia), particularly in hot weather. In some cases, hyperthermia can cause life-threatening medical problems.

Affected individuals tend to have sparse scalp and body hair (hypotrichosis). The hair is often light-colored, brittle, and slow-growing. This condition is also characterized by absent teeth (hypodontia) or teeth that are malformed. The teeth that are present are frequently small and pointed.

Hypohidrotic ectodermal dysplasia is associated with distinctive facial features including a prominent forehead, thick lips, and a flattened bridge of the nose. Additional features of this condition include thin, wrinkled, and dark-colored skin around the eyes; chronic skin problems such as eczema; and a bad-smelling discharge from the nose (ozena).

How common is hypohidrotic ectodermal dysplasia?

Hypohidrotic ectodermal dysplasia is the most common form of ectodermal dysplasia in humans. It is estimated to affect at least 1 in 17,000 people worldwide.

What genes are related to hypohidrotic ectodermal dysplasia?

Mutations in the EDA, EDAR, and EDARADD genes cause hypohidrotic ectodermal dysplasia.

The EDA, EDAR, and EDARADD genes provide instructions for making proteins that work together during embryonic development. These proteins form part of a signaling pathway that is critical for the interaction between two cell layers, the ectoderm and the mesoderm. In the early embryo, these cell layers form the basis for many of the body's organs and tissues. Ectoderm-mesoderm interactions are essential for the formation of several structures that arise from the ectoderm, including the skin, hair, nails, teeth, and sweat glands.

Mutations in the EDA, EDAR, or EDARADD gene prevent normal interactions between the ectoderm and the mesoderm and impair the normal development of hair, sweat glands, and teeth. The improper formation of these ectodermal structures leads to the characteristic features of hypohidrotic ectodermal dysplasia.

How do people inherit hypohidrotic ectodermal dysplasia?

Hypohidrotic ectodermal dysplasia has several different inheritance patterns. Most cases are caused by mutations in the EDA gene, which are inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. In about 70 percent of cases, carriers of hypohidrotic ectodermal dysplasia experience some features of the condition. These signs and symptoms are usually mild and include a few missing or abnormal teeth, sparse hair, and some problems with sweat gland function. Some carriers, however, have more severe features of this disorder.

Less commonly, hypohidrotic ectodermal dysplasia results from mutations in the EDAR or EDARADD gene. EDAR mutations can have an autosomal dominant or autosomal recessive pattern of inheritance, and EDARADD mutations have an autosomal recessive pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. Autosomal recessive inheritance means two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.

Where can I find information about treatment for hypohidrotic ectodermal dysplasia?

You may find information on treatment or management of hypohidrotic ectodermal dysplasia or some of its symptoms in the links below, particularly the links for Gene Reviews, MedlinePlus Encyclopedia, Educational resources, and Patient support.

Where can I find additional information about hypohidrotic ectodermal dysplasia?

You may find the following resources about hypohidrotic ectodermal dysplasia helpful. These materials are written for the general public.

  • MedlinePlus - Health information
    • Encyclopedia: Ectodermal dysplasia (http://www.nlm.nih.gov/medlineplus/ency/article/001469.htm)
    • Encyclopedia: Ozena (http://www.nlm.nih.gov/medlineplus/ency/article/001627.htm)
    • Encyclopedia: Sweating - absent (http://www.nlm.nih.gov/medlineplus/ency/article/003219.htm)
    • Health Topic: Skin Conditions (http://www.nlm.nih.gov/medlineplus/skinconditions.html)
    • Health Topic: Tooth Disorders (http://www.nlm.nih.gov/medlineplus/toothdisorders.html)
  • Educational resources - Information pages
    • Ask the Geneticist: Hypohidrotic ectodermal dysplasia (http://www.askthegen.org/question.php?question_id=1063)
    • Center for Craniofacial Developement and Disorders, Johns Hopkins Medicine (http://www.hopkinsmedicine.org/craniofacial/Education/DefinedArticle.cfm?MUArticleID=109&Source=Family)
    • Madisons Foundation (http://www.madisonsfoundation.org/index.php/component/option,com_mpower/diseaseID,577/)
    • Orphanet: Autosomal dominant hypohidrotic ectodermal dysplasia (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=1810)
    • Orphanet: Autosomal recessive hypohidrotic ectodermal dysplasia (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=248)
    • Orphanet: X-linked hypohidrotic ectodermal dysplasia (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=181)
    • Swedish Information Center for Rare Diseases (http://www.socialstyrelsen.se/en/rarediseases/Hypohidrotic+ectodermal+dysplasia.htm)
    • UC Davis Children's Hospital (http://www.ucdmc.ucdavis.edu/children/clinical_services/cleft_craniofacial/anomalies/ectodermal.html)
  • Patient support - For patients and families
    • National Foundation for Ectodermal Dysplasias (http://nfed.org/about_ed_types.asp)
    • National Organization for Rare Disorders (http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Hypohidrotic+Ectodermal+Dysplasia)
    • Resource list from the University of Kansas Medical Center (http://www.kumc.edu/gec/support/ectoderm.html)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

  • Gene Reviews - Clinical summary (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=x-hed)
  • Gene Tests - DNA tests ordered by healthcare professionals
    • Gene Tests: Hypohidrotic Ectodermal Dysplasia, Autosomal (http://www.genetests.org/query?testid=17164)
    • Gene Tests: Hypohidrotic Ectodermal Dysplasia, X-Linked (http://www.genetests.org/query?testid=2325)
  • ClinicalTrials.gov - Linking patients to medical research (http://clinicaltrials.gov/search/condition=%22hypohidrotic+ectodermal+dysplasia%22+OR+%22Ectodermal+Dysplasia%22+OR+%22Anhidrotic+Ectodermal+Dysplasias%22+OR+%22Christ-Siemens-Touraine+Syndrome%22)
  • PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=PubMed&term=(Ectodermal+Dysplasia[MAJR])+AND+((hypohidrotic+ectodermal+dysplasia[TIAB])+OR+(anhidrotic+ectodermal+dysplasia[TIAB])+OR+(christ-siemens-touraine+syndrome[TIAB])+OR+(cst+syndrome[TIAB])+OR+(hed[TIAB]))+AND+english[la]+AND+human[mh]&orig_db=PubMed&filters=ON&pmfilter_EDatLimit=1080+Days)
  • OMIM - Genetic disorder catalog
    • OMIM topic: Hypohidrotic ectodermal dysplasia, autosomal dominant (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=129490)
    • OMIM topic: Hypohidrotic ectodermal dysplasia, autosomal recessive (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=224900)
    • OMIM topic: Hypohidrotic ectodermal dysplasia, X-linked (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=305100)

What other names do people use for hypohidrotic ectodermal dysplasia?

  • Anhidrotic Ectodermal Dysplasia
  • Christ-Siemens-Touraine Syndrome
  • CST syndrome
  • HED

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about hypohidrotic ectodermal dysplasia?

  • See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
  • Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).
  • Submit your question to Ask the Geneticist (http://www.askthegen.org/).

What glossary definitions help with understanding hypohidrotic ectodermal dysplasia?

autosomal ; autosomal dominant ; autosomal recessive ; carrier ; cell ; chromosome ; chronic ; dysplasia ; ectoderm ; eczema ; embryo ; embryonic ; gene ; hyperthermia ; hypodontia ; hypohidrosis ; hypotrichosis ; inheritance ; inheritance pattern ; mesoderm ; mutation ; ozena ; pattern of inheritance ; protein ; recessive ; sex chromosomes ; sign ; symptom ; syndrome ; tissue ; trait ; X-linked recessive

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).

References
  • Drogemuller C, Distl O, Leeb T. X-linked anhidrotic ectodermal dysplasia (ED1) in men, mice, and cattle. Genet Sel Evol. 2003;35 Suppl 1:S137-45. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=12927086)
  • Gaide O. New developments in the history of hypohidrotic ectodermal dysplasia. Dermatology. 2003;207(2):123-4. No abstract available. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=12920356)
  • Gene Review: Hypohidrotic Ectodermal Dysplasia (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=x-hed)
  • Rouse C, Siegfried E, Breer W, Nahass G. Hair and sweat glands in families with hypohidrotic ectodermal dysplasia: further characterization. Arch Dermatol. 2004 Jul;140(7):850-5. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=15262696)
  • Wisniewski SA, Kobielak A, Trzeciak WH, Kobielak K. Recent advances in understanding of the molecular basis of anhidrotic ectodermal dysplasia: discovery of a ligand, ectodysplasin A and its two receptors. J Appl Genet. 2002;43(1):97-107. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=12084975)
  • Yavuz I, Baskan Z, Ulku R, Dulgergil TC, Dari O, Ece A, Yavuz Y, Dari KO. Ectodermal dysplasia: Retrospective study of fifteen cases. Arch Med Res. 2006 Apr;37(3):403-9. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=16513494)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: August 2006
Published: January 23, 2009