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Disease Profile

Woolly hair syndrome

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)

Woolly hair; Hereditary woolly hair (autosomal dominant); Familial woolly hair (autosomal recessive)


Congenital and Genetic Diseases; Skin Diseases


The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Orpha Number: 170

A rare congenital skin disease defined as an abnormality of the structure of the scalp hair and characterized by extreme kinkiness of the hair.

Prevalence of woolly hair is unknown.

Clinical description
Woolly hair can either be present at birth or appear in the first months of life. The curls, with an average diameter of 0.5 cm, lie closely together and usually make the hair difficult to comb; in addition, the hair may be more fragile than usual. The hair growth rate is usually normal but the anagen phase may be truncated, with the result that the hair does not grow to be long. Woolly hair either shows a generalized distribution affecting the entire scalp or a localized circumscribed distribution in the form of a woolly hair nevus. A diffuse partial form, manifesting during adolescence and adulthood, have also been described. In many cases, woolly hair is associated with hypotrichosis. Whilst wooly hair may occur as an isolated finding, it is important to exclude manifestations that occur in syndromic forms such as dilated cardiomyopathy and palmoplantar keratoderma (Carvajal syndrome), arrhythmogenic right ventricular cardiomyopathy and palmoplantar keratoderma (Naxos disease), or with growth failure and neurological symptoms (Menkes disease).

Isolated forms are mostly due to homozygous or sometimes compound heterozygous mutations in the genes lipase H (LIPH, 3q27.2) and lysophosphatidic acid receptor 6 (LPAR6, 13q14.2), that act along a common pathway which plays an important role in the control of hair growth as well as hair texture. In only very few patients, heterozygous mutations have been reported in two keratin genes, namely KRT74 (12q13.13) and KRT71 (12q13.13). Mutations have also been reported in KRT25 (17q21.2 ). Recently, a new gene locus was reported for woolly hair on chromosome 4q35.1-q35.2 with a potential disease gene with one affected family only. The etiology of diffuse partial woolly hair and of sporadically occurring woolly hair nevi is unknown.

Diagnostic methods
A thorough dermatological examination with an evaluation of the entire integument should be performed and may also identify any associated manifestations. The examination of the hair shafts by light and electron microscopy reveals an elliptical cross section, variations in caliber, axis rotation and kinked formation, as well as non-homogeneous keratinization. In some cases trichorrexis nodosa is evident. If necessary, the anagen/catagen ratio can be determined using a trichogram. In cases of diffuse partial woolly hair, an increase in intermediate follicles can be detected histopathologically.

Differential diagnosis
Differential diagnosis includes acquired progressive curling of the hair, allotrichia circumscripta symmetrica, acquired partial kinky hair and drug-induced kinky hair. Syndromes with woolly hair should also be excluded, such as Naxos disease, Carvajal syndrome, Woolly hair-hypotrichosis-everted lower lip-outstanding ears syndrome, woolly-hair-palmoplantar keratoderma syndrome, and skin fragility-woolly hair-palmoplantar keratoderma syndrome.

Genetic counseling
Generalized forms due to KRT74 and KRT71 mutations are autosomal dominant, and forms due to LIPH and LPAR6 mutations are autosomal recessive. Sporadic forms may also occur. Follicular mosaicism is likely, while an autosomal dominant transmission has also been discussed for diffuse partial woolly hair.

Management and treatment
No treatment is currently available. Depending on their size and location, woolly hair nevi can be excised. Harsh physical and chemical cosmetic treatments should be avoided. If the presence of a syndrome is suspected, an extensive internal investigation, with a detailed cardiological diagnostic examination, is necessary.

Woolly hair is most pronounced during childhood; the manifestations often become less severe in adulthood.

Visit the Orphanet disease page for more resources.


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
Brittle hair
Fine hair
Fine hair shaft
Fine hair texture
Thin hair shaft
Thin hair texture

[ more ]

Woolly hair
Kinked hair
30%-79% of people have these symptoms
Hypopigmentation of hair
Loss of hair color
Slow-growing hair
Slow growing hair
Slow rate of hair growth
Slow speed of hair growth

[ more ]

5%-29% of people have these symptoms
Abnormal pupil morphology
Abnormality of the pupil
Pupillary abnormalities
Pupillary abnormality

[ more ]

Abnormal retinal morphology
Retina issue
Clouding of the lens of the eye
Cloudy lens

[ more ]

Sparse body hair
Sparse lateral eyebrow
Limited hair on end of eyebrow
Squint eyes

[ more ]


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.

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.
  • 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 Woolly hair syndrome. Click on the link to view a sample search on this topic.