Ichthyosis, Trichothiodystrophy

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Ichthyosis, Trichothiodystrophy is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • TTD
  • Tay Syndrome
  • IBIDS Syndrome
  • PIBIDS Syndrome

Disorder Subdivisions

  • None

General Discussion

Trichothiodystrophy is a hereditary disorder characterized by brittle hair, which may be accompanied by a variety of other manifestations. It is sometimes called PIBIDS, a term that refers to the association of Photosensitivity Ichthyosis, Brittle hair, Intellectual impairment, Decreased fertility, and Short stature. Without photosensitivity the condition has been termed IBIDS, and without ichthyosis, BIDS. Many patients have recurrent infections, and abnormalities of the bone and teeth may also occur.

The defining feature of trichothiodystrophy is brittle hair, which is sulfur deficient and, when examined with a microscope and polarized light, demonstrates a characteristic light and dark (tiger tail) banding.


Trichothiodystrophy is characterized by brittle hair that is low in sulfur content. The skin in many areas of the body may be covered with fine, dark scales (ichthyosis). Evidence of the ichthyosis may be present at birth in the form of a parchment-like (collodion) membrane. Patients usually have short stature and may have developmental delay and recurrent infections. Patients' skin may burn easily after minimal exposure to ultraviolet radiation (e.g., sun) and their eyes may be bothered by strong light (photophobia). Nails may be abnormally short, broad and ridged, and they may split easily. Loss of subcutaneous fat may result in a prematurely old-looking face and there may be a beaked nose, receding chin, and protruding ears.

The central nervous system may be affected with seizures, tremors, lack of muscle coordination, and nerve deafness. The testes may fail to descend (cryptorchidism) in males and female genitalia may be underdeveloped. In women, breast tissue may be completely absent in spite of normal development of the nipples. Very small cataracts may occur in the eyes. Bone and teeth abnormalities appear in some cases


Trichothiodystrophy is a hereditary disorder transmitted as an autosomal recessive trait. Human traits, including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother. In recessive disorders, the condition does not appear unless a person inherits the same defective gene for the same trait from each parent. If the individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease but usually will not show symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is approximately 25 percent per pregnancy. Many patients with trichothiodystrophy have abnormalities in genes involved in the repair of DNA damage.

Affected Populations

Trichothiodystrophy is usually present at birth. Males and females are affected in equal numbers.

Standard Therapies

Patients who are photosensitive must be protected from exposure to the sun and other sources of ultraviolet radiation. Monitoring for developmental delay with special educations services may be required in school. Skin symptoms of ichthyosis (dry skin) are treated by applying skin softening emollients and keratolytics (products containing alpha-hydroxy acids). This can be particularly effective after bathing while the skin is still moist. Individuals with frequent infections may benefit for prophylactic antibiotics. Genetic counseling may be beneficial for families of children with trichothiodystrophy.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:




Sybert, VP. Ichthyosis. In: NORD Guide to Rare Disorders. Lippincott, Williams & Wilkins. Philadalphia, PA. 2003:120-21.

DiGiovanna JJ: Ichthyosiform Dermatoses. In Freedberg IM, et al (Eds), Fitzpatrick's Dermatology in General Medicine, 6th Edition. McGraw-Hill, New York, 2003;51:481-505.


DiGiovanna, JJ, Robinson-Bostom, L. Ichthyosis: etiology, diagnosis, and management. Am J Clin Dermatol. 2003;4: 81-95.

Williams, ML, et al. Genetically Transmitted, Generalized Disorders of Cornification. The Ichthyoses. Dermatol Clin. January 1987; 5(1): 155-78.

Happle, R, et al. The Tay Sydrome (Congenital Ichthyosis with Trichothiodystrophy). European Journal Pediatr. January 1984;141(3): 147 /152.


Foundation for Ichthyosis & Related Skin Types

2616 N Broad Street

Colmar, PA 18915

Tel: (215)997-9400

Fax: (215)997-9403

Tel: (800)545-3286

Email: info@firstskinfoundation.org

Internet: http://www.firstskinfoundation.org

NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases

Information Clearinghouse

One AMS Circle

Bethesda, MD 20892-3675


Tel: (301)495-4484

Fax: (301)718-6366

Tel: (877)226-4267

TDD: (301)565-2966

Email: NIAMSinfo@mail.nih.gov

Internet: http://www.niams.nih.gov/

National Registry for Ichthyosis and Related Disorders

University of Washington

Dermatology Dept. Box 356524

1959 N.E. Pacific Street

Seattle, WA 98195-6524

Tel: (800)595-1265

Email: info@skinregistry.org

Internet: http://www.skinregistry.org/

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223

Internet: http://rarediseases.info.nih.gov/GARD/

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.