Linear verrucous nevus syndrome

What it is

From: Orphanet

A rare skin disease characterized by a hamartomatous epidermal lesion presenting as a linear array of verrucous, hyperkeratotic papules that often coalesce into plaques and are formed along the lines of Blaschko. The condition is associated with involvement of other organ systems, mainly brain, eye, and skeletal system. It is the result of mosaic post-zygotic mutations and most commonly presents at birth, but may occur anytime during childhood, rarely also in adulthood.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Astrocytoma · Very frequent (99-80%)

Astrocytoma is a neoplasm of the central nervous system derived from astrocytes. Astrocytes are a type of glial cell, and thus astrocytoma is a subtype of glioma.

Hyperkeratosis · Very frequent (99-80%)

Hyperkeratosis is a histopathological term defining a thickened stratum corneum and may be present in many different skin conditions, with many possible overlaps. Hyperkeratosis refers to the increased thickness of the stratum corneum, the outer layer of the skin. Hyperkeratosis is subclassified as orthokeratotic or parakeratotic. Orthokeratotic hyperkeratosis refers to the thickening of the keratin layer with preserved keratinocyte maturation, while parakeratotic hyperkeratosis shows retained nuclei as a sign of delayed maturation of keratinocytes.

Macrocephaly · Very frequent (99-80%)

Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.

Neoplasm of the central nervous system · Very frequent (99-80%)

A neoplasm of the central nervous system.

Sparse scalp hair · Very frequent (99-80%)

Decreased number of hairs per unit area of skin of the scalp.

Verrucous papule · Very frequent (99-80%)

A wartlike (with multiple small elevated projections) papule.

Mental deterioration · Frequent (79-30%)

Loss of previously present mental abilities, generally in adults.

Seizure · Frequent (79-30%)

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Abnormal cornea morphology · Occasional (29-5%)

Any abnormality of the cornea, which is the transparent tissue at the front of the eye that covers the iris, pupil, and anterior chamber.

Abnormal skull morphology · Occasional (29-5%)

An abnormality of the skull, the bony framework of the head which is comprised of the neurocranium (with eight cranial bones) and the viscerocranium (facial skeleton) that comprises fourteen facial bones with the mandible as its largest bone.

Abnormality of the kidney · Occasional (29-5%)

An abnormality of the kidney.

Aplasia/Hypoplasia of the corpus callosum · Occasional (29-5%)

Absence or underdevelopment of the corpus callosum.

Aplasia/Hypoplasia of the fovea · Occasional (29-5%)

Congenital absence or underdevelopment of the fovea.

Cataract · Occasional (29-5%)

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.

Other findings in the same source

From: Orphanet

Additional reported features include Dandy-Walker malformation (Occasional (29-5%)); Genu recurvatum (Occasional (29-5%)); Hypophosphatemia (Occasional (29-5%)); Iris coloboma (Occasional (29-5%)); Reduced bone mineral density (Occasional (29-5%)); Retinopathy (Occasional (29-5%)); Scoliosis (Occasional (29-5%)); Short metacarpal (Occasional (29-5%)); Skeletal dysplasia (Occasional (29-5%)); Strabismus (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Neonatal

Which doctor should you see?

The suggested department for discussing Linear verrucous nevus syndrome is Dermatology, with a dermatologist as the relevant type of clinician. Dermatologist; paediatric services for children as appropriate.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which features of the skin, hair or nails distinguish the possibilities?
• Would photographs over time help document the changes?
• What should be expected from treatment, and how will irritation or other adverse effects be managed?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Linear verrucous nevus syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.