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Epidermal Nevus with Woolly Hair: A Case Report
Aviya Muallem1, Tamar Harel2, Michal Neumark1
1Department of Dermatology, The Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical Center, Jerusalem, Israel.
Clinical and Experimental Dermatology
|June 18, 2026
Summary
Mosaic RASopathies, a rare genetic condition, can cause epidermal nevus and woolly hair. A recent case highlights a HRAS mutation linked to these symptoms and neurological issues in a young boy.
Area of Science:
- Genetics
- Dermatology
- Neurology
Background:
- Epidermal nevus and woolly hair are rare manifestations.
- Mosaic RASopathies result from postzygotic HRAS mutations.
- These conditions can present with complex phenotypes.
Purpose of the Study:
- To report a rare case of coexisting epidermal nevus and woolly hair.
- To identify the genetic basis of the condition in the reported patient.
- To expand the understanding of HRAS-related mosaic RASopathies.
Main Methods:
- Clinical examination of a 1-year-old boy.
- Genetic testing of lesional skin.
- Analysis of HRAS mutation (c.34G>A, p.Gly12Ser).
Main Results:
- The patient presented with ipsilateral epidermal nevus and localized woolly hair.
- Right frontal encephalomalacia and developmental delay were observed.
- A mosaic HRAS mutation was confirmed in the lesional skin.
Conclusions:
- This case expands the known spectrum of HRAS-related mosaic RASopathies.
- It underscores the association between epidermal nevus, woolly hair, and neurological involvement.
- Highlights the importance of genetic testing in diagnosing complex mosaic conditions.
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