What are the other Names for this Condition? (Also known as/Synonyms)

• ACC of Vertex
• Aplasia Cutis Congenita of the Vertex
• Congenital Defect of the Skull and Scalp

What is Circumscribed Cutaneous Aplasia of the Vertex? (Definition/Background Information)

• Circumscribed Cutaneous Aplasia of the Vertex may be described as a type of aplasia cutis congenita (ACC). ACC constitute a group of rare congenital disorders in which, certain layers of the skin are absent from one or multiple areas on the newborn’s body
• In Circumscribed Cutaneous Aplasia of the Vertex, the scalp skin on top of the head (called the vertex), and sometimes, the underlying bone is absent at birth. The cause of the condition is not well-understood, but is associated with several factors such as teratogens, injury, and congenital fetal defects
• A management of Circumscribed Cutaneous Aplasia of the Vertex may involve wound (lesion) care and surgery, based on the healthcare provider’s evaluation. However, the overall outcomes depend on the severity of the condition and extent of brain involvement, if any noted. Typically, children with mild conditions have better prognoses than those presenting severe symptoms and/or complications

Who gets Circumscribed Cutaneous Aplasia of the Vertex? (Age and Sex Distribution)

• Circumscribed Cutaneous Aplasia of the Vertex is a congenital disorder, and the presentation of symptoms may occur at birth
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected. However, the condition is exceedingly rare

What are the Risk Factors for Circumscribed Cutaneous Aplasia of the Vertex? (Predisposing Factors)

The risk factors for Circumscribed Cutaneous Aplasia of the Vertex may include:

• Exposure to chemicals during pregnancy that can cause birth defects in fetus, called teratogens. Such chemicals include methimazole, carbimazole, misoprostol, and valproic acid
• Trauma to the uterus during pregnancy
• A positive family history, since Circumscribed Cutaneous Aplasia of the Vertex can be inherited. Children born to consanguineous partners or spouses have a higher risk for the condition

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Circumscribed Cutaneous Aplasia of the Vertex? (Etiology)

Circumscribed Cutaneous Aplasia of the Vertex may be caused by the following factors:

• Exposure to teratogens during pregnancy that may harm the developing fetus
• Amniotic adhesion
• An abnormality in development of blood vessels to the skin
• Use of pharmacological agents such as methimazole and benzodiazepines)
• Intrauterine trauma during pregnancy
• Infections during pregnancy
• Incomplete closure of ectodermal fusion lines
• Genetic factors: When ACC of Vertex occurs as an inherited disorder, it may either follow autosomal dominant or autosomal recessive patterns of inheritance

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Circumscribed Cutaneous Aplasia of the Vertex?

The signs and symptoms of Circumscribed Cutaneous Aplasia of the Vertex may vary in type and severity among affected individuals. It also depends on the underlying causative condition and its severity. The signs and symptoms may include:

• Absence of skin on the scalp (at the vertex), which is noted at birth
• Children may also show an absence of underlying bony structures at the vertex (bony defect)
• This is known as aplasia cutis congenita (ACC) lesion at birth that typically manifest as lesions on the scalp
• Ulceration of skin lesion
• Bleeding from the scalp that can be severe
• Hair loss in the affected region of scalp
• Some children may present toe, finger, or limb abnormalities

How is Circumscribed Cutaneous Aplasia of the Vertex Diagnosed?

If Circumscribed Cutaneous Aplasia of the Vertex is suspected, then the healthcare provider may undertake further investigations and perform detailed brain scans to study and assess the extent of the accompanying skull and brain malformations.

Circumscribed Cutaneous Aplasia of the Vertex is diagnosed on the basis of the following information:

• Physical examination of the individual and family medical history evaluation
• Brain scans are conducted to determine if the corpus callosum has been formed or not. These may include 
• Prenatal studies including ultrasound scans
• CT or MRI brain scans after birth of the child
• Dermoscopy: Dermoscopy is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Skin biopsy: A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Circumscribed Cutaneous Aplasia of the Vertex?

The complications of Circumscribed Cutaneous Aplasia of the Vertex may include:

• Persistent skin discoloration
• Irreversible alopecia
• Secondary bacterial or fungal infections
• Emotional stress for the parents and caregivers
• Severe bleeding causing life-threatening medical emergencies
• Potential brain injury

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Circumscribed Cutaneous Aplasia of the Vertex Treated?

The treatment of Circumscribed Cutaneous Aplasia of the Vertex is usually given to manage the signs and symptoms and any complications that develops. It may include:

• Conservative treatment measures to help heal the lesion:
  • Wound cleansing and care
  • Application of topical antiseptics
  • Use of hydrocolloidal dressings 
• If necessary, surgical repairs may be undertaken through skin flaps and grafts, especially if the condition is severe and the lesion is large-sized

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

How can Circumscribed Cutaneous Aplasia of the Vertex be Prevented?

Prevention of Circumscribed Cutaneous Aplasia of the Vertex may not be generally possible. 

• If Circumscribed Cutaneous Aplasia of the Vertex occurs due to heritable genetic causes, the condition is not preventable
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Pregnant women may greatly reduce their risk by avoiding exposure to chemicals such as methimazole, carbimazole, misoprostol, valproic acid, and benzodiazepines
• A careful and periodic monitoring of the pregnancy is advised and recommended

Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders.

What is the Prognosis of Circumscribed Cutaneous Aplasia of the Vertex? (Outcomes/Resolutions)

The prognosis of Circumscribed Cutaneous Aplasia of the Vertex is dependent upon the severity of the signs and symptoms and associated complications, if any.

• In children with mild cases, the condition may show improvement and regress within a few weeks to months
• If the condition is severe, the outcomes may be unpredictable and even life-threatening. Deaths have been reported in cases presenting severe complications

Additional and Relevant Useful Information for Circumscribed Cutaneous Aplasia of the Vertex:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/