Nonsyndromic aplasia cutis congenita

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Nonsyndromic aplasia cutis congenita is a condition in which babies are born with localized areas of missing skin (lesions). These areas resemble ulcers or open wounds, although they are sometimes already healed at birth. Lesions most commonly occur on the top of the head (skull vertex), although they can be found on the torso or limbs. In some cases, the bone and other tissues under the skin defect are also underdeveloped.

Most affected babies have a single lesion. The lesions vary in size and can be differently shaped: some are round or oval, others rectangular, and still others star-shaped. They usually leave a scar after they heal. When the scalp is involved, there may be an absence of hair growth (alopecia) in the affected area.

When the underlying bone and other tissues are involved, affected individuals are at higher risk of infections. If these severe defects occur on the head, the membrane that covers the brain (the dura mater) may be exposed, and life-threatening bleeding may occur from nearby vessels.

Skin lesions are typically the only feature of nonsyndromic aplasia cutis congenita, although other skin problems and abnormalities of the bones and other tissues occur rarely. However, the characteristic skin lesions can occur as one of many symptoms in other conditions, including Johanson-Blizzard syndrome and Adams-Oliver syndrome. These instances are described as syndromic aplasia cutis congenita.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Nonsyndromic aplasia cutis congenita can have different causes, and often the cause is unknown. Because the condition is sometimes found in multiple members of a family, it is thought to have a genetic component; however, the genetic factors are not fully understood. Researchers suggest that genes important for skin growth may be involved. It is thought that impairments of skin growth more commonly affect the skin at the top of the head because that region needs to be able to grow quickly to cover the fast-growing skull of a developing baby.

In some cases, nonsyndromic aplasia cutis congenita is caused by exposure to a drug called methimazole before birth. This medication is given to treat an overactive thyroid gland. Babies whose mothers take this medication during pregnancy are at increased risk of having the condition. In addition, certain viral infections in a pregnant mother can cause the baby to be born with the skin lesions characteristic of nonsyndromic aplasia cutis congenita. Other cases are thought to be caused by injury to the baby during development.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Most cases of nonsyndromic aplasia cutis congenita are sporadic, which means they occur in people with no history of the disorder in their family. When the condition runs in families, inheritance usually follows an autosomal dominant pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder. Rarely, the condition appears to follow an autosomal recessive pattern of inheritance, which means both copies of a gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Aplasia cutis congenita affects approximately 1 in 10,000 newborns. The incidence of the nonsyndromic form is unknown.

Which doctor should you see?

The suggested department for discussing Nonsyndromic aplasia cutis congenita is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

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.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Nonsyndromic aplasia cutis congenita. 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.