Rare Pediatrics News

Disease Profile

Twenty-nail dystrophy

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)

Autosomal dominant nail dysplasia; Idiopathic trachyonychia; Trachyonychia;


Congenital and Genetic Diseases; Connective tissue diseases; Skin Diseases


Twenty-nail dystrophy is a condition that affects the nails of the fingers and toes. The nails become rough, thin, and brittle. They appear similar to sandpaper. It was once thought that all 20 nails will be affected, but any number of nails can become rough and brittle. This condition most commonly occurs in childhood, but it can occur at any age. The exact cause is often unknown, but sometimes appears with other skin conditions such as lichen planus, psoriasis and alopecia areata. In some people, the symptoms of twenty-nail dystrophy improve or disappear over time, but in other people they persist for a long time.[1]


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:
5%-29% of people have these symptoms
Thick nail
Thickened nails

[ more ]

Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance
Detachment of nail
Slow progression
Signs and symptoms worsen slowly with time
Thin nail
Thin nails


The cause of twenty-nail dystrophy is unknown. In some cases, twenty-nail dystrophy has been diagnosed in people who also have another condition such as alopecia areata, or psoriasis.[1] There are a few reported cases where several members of the same family have been affected by this condition, which suggests that there may be a genetic cause.[2]

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

  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.

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 Twenty-nail dystrophy. Click on the link to view a sample search on this topic.


  1. Jacobsen AA, Tosti A. Trachyonychia and Twenty-Nail Dystrophy: A Comprehensive Review and Discussion of Diagnostic Accuracy. Skin Appendage Disord. September 2016; 2(1-2):7-13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5096243/.
  2. Nail Disorder, Nonsyndromic Congenital 1. Online Mendelian Inheritance in Man (OMIM). August 11, 2011; https://www.omim.org/entry/161050.

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