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Disease Profile

Pili torti

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Twisted hair; Coarse, dry, lusterless hair which breaks off easily


Congenital and Genetic Diseases; Skin Diseases


Pili torti is a rare hair condition characterized by fragile hair. In pili torti hair has a flattened shaft with clusters of narrow twists at irregular intervals.[1] Some cases may be inherited in autosomal dominant or autosomal recessive patterns, while others are acquired.[1][2] In the inherited form, symptoms tend to be present from early childhood. It can occur alone or as part of other diseases like ectodermal dysplasias, Menke disease, Bjornstand syndrome, or Bazex syndrome. Acquired cases of pili torti may be associated with anorexia nervosa, malnutrition, oral retinoid treatment, or inflammatory scalp conditions (e.g., cutaneous lupus erythematousus). If pili torti is detected, it is necessary to investigate possible neurological disorders, hearing loss, and defects in the hair, nails, sweat glands and teeth.[1] There is no specific treatment for this condition, but it may improve spontaneously after puberty.[2] Click here to visit Medscape and view an image of a child with pili torti.


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Pili torti
Flattened and twisted hair
30%-79% of people have these symptoms
Abnormal eyebrow morphology
Abnormality of the eyebrow
Abnormality of dental enamel
Abnormal tooth enamel
Enamel abnormalities
Enamel abnormality

[ more ]

Abnormality of the nail
Hair loss
Brittle hair
5%-29% of people have these symptoms
Hearing impairment
Hearing defect

[ more ]

Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
Autosomal recessive inheritance
Coarse hair
Coarse hair texture
Dry hair
Hair shafts flattened at irregular intervals and twisted through 180 degrees about their axes
Hypoplasia of dental enamel
Underdeveloped teeth enamel
No previous family history


In acquired pili torti, treatment involves stopping the exposure to the causative agent (e.g., to oral retinoids) or condition (e.g., improving diet).[1] There is no specific treatment for the inherited form of pili torti. It may improve spontaneously after puberty. If pili torti is detected, further evaluation to investigate possible neurological disorders, problems with hair, teeth or nails (ectodermal disturbances) and hearing loss is mandatory.[2] It is generally recommended that people with pili torti try to avoid trauma to the hair.[1][3] Suggestions include, sleeping on a satin pillowcase, avoiding excessive grooming, braiding, heat treatments, dying and coloring, reducing exposure to sunlight (wear a hat), using gentle shampoos diluted in warm water, adding conditioner to freshly washed hair, avoiding use of a hair dryer (or using it on cool setting), and avoiding oral retinoids (e.g., isotretinoin, acitretin) if possible.[3][1] Some individuals with pili torti choose to wear a wig.[1]


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • DermNetNZ provides information on defects of the hair shaft, which includes information on pili torti. DermNetNZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated.

      In-Depth Information

      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
      • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Pili torti. Click on the link to view a sample search on this topic.

        Selected Full-Text Journal Articles


          1. Defects of the hair shaft. DermNet NZ. 2010; https://www.dermnetnz.org/hair-nails-sweat/hair-shaft-defects.html. Accessed 2/23/2011.
          2. Yang JJH, Cade KV, Rezende FC, Pereira JM & Pegas JRP. Clinical presentation of pili torti Case report. An Bras Dermatol. 2015; 90(3) Suppl 1:S29-31.. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4540501/#r01. Accessed 12/28/2015.
          3. Gelles LN. Picture of the month. Pili torti. Arch Pediatr Adolesc Med. 1999 Jun; https://archpedi.ama-assn.org/cgi/content/full/153/6/647. Accessed 2/23/2011.

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