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Adams-Oliver Syndrome (AOS) is a rare genetic disorder that is characterized by abnormalities of the scalp and skull, and defects in the development of the arms and legs.

The most common features of AOS include a congenital scalp defect (a patch of missing or poorly developed scalp), aplasia cutis (absence of skin), and terminal transverse limb defects (absence or underdevelopment of the fingers or toes).

Adams–Oliver Syndrome :‎ [MEDNOTES+MINDMAP]

  • Definition:
    • Rare genetic disorder characterized by abnormalities of the scalp and skull, as well as abnormalities of the limbs (such as missing or underdeveloped fingers and toes)
  • Epidemiology:
    • Prevalence is unknown, but believed to be rare. Occurs in both males and females, and can be inherited from a parent or occur spontaneously.
  • Natural history:
    • Symptoms usually present at birth or shortly thereafter. Severity can vary greatly, with some individuals experiencing only mild abnormalities and others experiencing more severe deformities.
  • Classification/Types/Stages:
    • Type 1: Characterized by abnormalities of the scalp and skull, as well as abnormalities of the limbs (such as missing or underdeveloped fingers and toes).
    • Type 2: Characterized by abnormalities of the scalp and skull, as well as abnormalities of the heart.
    • Stages:
      • Stage 1: Mild abnormalities of the scalp and skull, with normal limb development.
      • Stage 2: Moderate abnormalities of the scalp and skull, with mild to moderate abnormalities of the limbs.
      • Stage 3: Severe abnormalities of the scalp and skull, with severe abnormalities of the limbs.

Risk Factors:

  • AOS is an inherited disorder caused by mutations in the ARHGAP31 gene. It is inherited in an autosomal dominant manner, meaning that a person only needs to inherit the mutated gene from one parent to develop the condition.
  • AOS is a rare condition, with an estimated prevalence of 1 in 250,000 live births.

Etiology/Causes:

  • AOS is caused by mutations in the ARHGAP31 gene, which plays a role in the development of the scalp, limbs, and cardiovascular system.
  • These mutations can occur spontaneously or can be inherited from a parent with the mutated gene.

Signs:

  • Absence of the scalp (aplasia cutis)
  • Partial or complete absence of fingers and toes (syndactyly)
  • Various cardiovascular abnormalities such as aortic stenosis, patent ductus arteriosus, and pulmonary stenosis

Symptoms:

  • Lack of hair on the scalp
  • Missing or partially formed fingers and toes
  • Heart abnormalities can cause symptoms such as difficulty breathing, fatigue, and cyanosis (bluish skin and mucous membranes)

Pathology/Pathogenesis:

  • The ARHGAP31 gene provides instructions for making a protein called RhoGAP that helps regulate the activity of small proteins called Rho GTPases. These proteins play a role in the development and function of cells in the body.
  • Mutations in the ARHGAP31 gene result in the production of an abnormal RhoGAP protein or the absence of the protein altogether. This can disrupt the normal development of the scalp, limbs, and cardiovascular system, leading to the characteristic features of AOS.

Diagnosis:

  • Diagnosis is typically made based on clinical presentation and genetic testing
  • Physical exam to assess for presence of scalp defects and limb abnormalities
  • Genetic testing to confirm diagnosis and identify specific genetic mutation
  • Other diagnostic tests may include imaging studies (CT scan, MRI) to assess for any internal abnormalities

Tests Required:

  • Physical exam
  • Genetic testing
  • Imaging studies (CT scan, MRI)

Associated with:

  • Scalp defects (aplasia cutis congenita)
  • Limb abnormalities (syndactyly, polydactyly)
  • Congenital heart defects
  • Vascular abnormalities

Similar diseases/syndromes:

  • Apert syndrome
  • Pfeiffer syndrome
  • Saethre-Chotzen syndrome
  • Toriello-Carey syndrome

Treatment:

  • Treatment depends on the specific abnormalities present in the individual
  • Surgery may be necessary to correct any abnormalities or defects present at birth
  • Physical therapy may be required to improve mobility and function in affected limbs
  • Genetic counseling may be recommended to discuss the possibility of passing on the genetic mutation to future offspring
 

Dr. Arin Nandi

Passionate About Medical Science & Helping Future Doctors Achieve Top Ranks In Medical Exams. He is professionally a dentist as well as a public health expert from JIPMER working in govt.health department
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