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Disease Profile

Linear and whorled nevoid hypermelanosis

Prevalence
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.

Unknown

Age of onset

Infancy

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ICD-10

L81.4

Inheritance

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

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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

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X-linked
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.

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

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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.

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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.

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Not applicable

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Other names (AKA)

LWNH; Nevoid hypermelanosis, linear and whorled; Linear and whorled hypermelanosis;

Categories

Congenital and Genetic Diseases; Skin Diseases

Summary

Linear and whorled nevoid hypermelanosis (LWNH) is a rare benign condition affecting skin pigment occurring in newborns or early infancy. The primary symptom is swirling streaks of darkened (hyperpigmented) skin, mainly on the trunk and limbs. The dark streaks appear along the lines of normal skin development (lines of Blaschko). LWNH typically spreads for one to two years and then becomes stable. The dark streaks sometimes fade with age. Most of the time, only the skin is affected, but other conditions, such as growth, developmental, or heart problems may be present. The cause for LWNH is unknown. Genetic factors, especially chromosomal mosaicism, may be involved. LWNH is not thought to be inherited. It is diagnosed based on the symptoms. There is no specific treatment for the skin findings in LWNH because they are not associated with any medical problem.[1][2][3]

Symptoms

The following list includes the most common signs and symptoms in people with linear and whorled nevoid hypermelanosis (LWNH). These features may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list does not include every symptom or feature that has been described in this condition. 

Symptoms may include:[1][4]

  • Swirling streaks of darkened (hyperpigmented) skin
  • Developmental delay
  • Asymmetric growth
  • Cardiovascular defects

The dark skin streaks appear in early infancy and are generally found on the trunk and limbs. The face, palms of the hand, and soles of the feet are not generally affected. The hyperpigmentation may get progress for a few years, and then become stable.[4][5]. In some people, the darkened skin streaks fade with time.[3] Most people with LWNH have no medical problems related to their condition.

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:
HPO ID
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
0000006
Eosinophilia
High blood eosinophil count
0001880
Hyperpigmented streaks
0007572
Infantile onset
Onset in first year of life
Onset in infancy

[ more ]

0003593
Sporadic
No previous family history
0003745

Cause

The exact cause of linear and whorled nevoid hypermelanosis (LWNH) is not known. It is thought to result from a genetic change called mosaicism, that occurs early in the development of an embryo.[3][4] People with mosaicism have two sets of cells each with a different genetic makeup.

Several chromosome abnormalities have been reported in affected individuals.[6] People with LWNH who have an underlying chromosome abnormality are more likely to have symptoms in addition to those that affect the skin.[4]

Treatment

There is no specific treatment for linear and whorled nevoid hypermelanosis (LWNH). It is considered a mild condition and no medical treatment may be necessary. Methods to lighten the skin including chemical peels and laser treatments may be helpful. Due to the possible association with chromosome abnormalities and other conditions, people with LWNH should be evaluated for developmental delays, growth delays, skeletal abnormalities, and congenital heart defects.[2][3][5]

One specialist who might be involved in the care of someone with LWNH is a dermatologist.

Organizations

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 Providing General Support

    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 provides information on the lines of Blaschko on their website.
    • MedlinePlus, the National Library of Medicine Web site designed to help you research your health questions, provides information on pigmentation disorders.

      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 Linear and whorled nevoid hypermelanosis. Click on the link to view a sample search on this topic.

        Resources for Kids

          References

          1. Nevoid hypermelanosis, linear and whorled; LWNH. OMIM. Updated 10/24/2016; https://omim.org/entry/614323.
          2. Di Lernia V. Linear and whorled hypermelanosis review. Pediatr Dermatol. 2007; 24(3):205-210. https://pubmed.ncbi.nlm.nih.gov/17542865.
          3. Sinha P, Chatterjee M, Singh KK, Sood A. Linear and Whorled Nevoid Hypermelanosis with Depigmentation. Indian Dermatol Online J. 2017; 8(2):131-133. https://pubmed.ncbi.nlm.nih.gov/28405555.
          4. Mehta V, Vasanth V, Balachandran C, Mathew M. Linear and whorled nevoid hypermelanosis. Int J Dermatol. Apr 2011; 50(4):491-2. https://pubmed.ncbi.nlm.nih.gov/21413967.
          5. Vashi N, Kundu R. Congenital and inherited hyperpigmentation disorders. UpToDate. Waltham, MA: UpToDate; Updated Nov 12, 2019; https://uptodate.com/contents/congenital-and-inherited-hyperpigmentation-disorders.
          6. Yao L, Zhou DD, Lu CW. Linear and Whorled Nevoid Hypermelanosis. Am J Med Sci. January, 2017; 353(1):1-3.
          7. Metta AK, Ramachandra S, Sadath N, Manupati S. Linear and whorled nevoid hypermelanosis in three successive generations. Indian J Dermatol Venereol Leprol. May-June, 2011; 77(3):403.

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