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Auriculo-Condylar Syndrome

Last updated April 30, 2018

Approved by: Krish Tangella MD, MBA, FCAP

Auriculo-Condylar Syndrome (ACS) presents with bilateral external ear malformations ('Question Mark' Ears), mandibular condyle hypoplasia, microstomia, micrognathia, microglossia and facial asymmetry.

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

  • Auriculocondylar Syndrome
  • Prominent and Constricted Ears
  • Question Mark Ear

What is Auriculo-Condylar Syndrome? (Definition/Background Information)

  • Auriculo-Condylar Syndrome (ACS) presents with bilateral external ear malformations ('Question Mark' Ears), mandibular condyle hypoplasia, microstomia, micrognathia, microglossia and facial asymmetry
  • Additional manifestations include hypotonia, ptosis, cleft palate, puffy cheeks, developmental delay, impaired hearing and respiratory distress
  • Auriculo-Condylar Syndrome is transmitted in an autosomal dominant manner

(Source: Auriculocondylar Syndrome; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

Who gets Auriculo-Condylar Syndrome? (Age and Sex Distribution)

  • Auriculo-Condylar Syndrome is a rare congenital disorder, reported in about 12 individuals in six multigenerational families
  • The presentation of symptoms may occur in the neonatal period or during infancy
  • Both males and females may be affected
  • Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Auriculo-Condylar Syndrome? (Predisposing Factors)

  • A positive family history may be an important risk factor, since Auriculo-Condylar Syndrome can be inherited
  • Currently, no other risk factors have been clearly identified for the syndrome

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 Auriculo-Condylar Syndrome? (Etiology)

Auriculo-Condylar Syndrome may be caused by mutation(s) in GNA13 or PLCB4 genes.

  • The proteins coded by these genes are involved in cellular signaling
  • During embryonic development, these genes play important roles in the development of the first and second pharyngeal arches, which ultimately form the ears, jawbones and facial muscles 

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 dominant mutation with reduced penetrance may lead to an affected individual exhibiting milder or no symptoms, indicating that factors other than the causative gene mutation may play a role in the manifestation of symptoms.

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 Auriculo-Condylar Syndrome?

The signs and symptoms of Auriculo-Condylar Syndrome may include:

  • Anterior open-bite malocclusion
  • Apnea
  • Chewing difficulties
  • Cleft at the superior portion of the pinna
  • Cupped ear
  • Dental crowding
  • Dental malocclusion
  • Hypoplastic superior helix
  • Glossoptosis
  • Low-set ears
  • Macrocephaly
  • Mandibular condyle aplasia
  • Mandibular condyle hypoplasia
  • Micrognathia
  • Narrow mouth
  • Overfolding of the superior helices
  • Postauricular skin tag
  • Posteriorly rotated ears
  • Preauricular skin tag
  • Round face
  • Stenosis of the external auditory canal
  • Snoring
  • Speech articulation difficulties

(Source: Auriculo-Condylar Syndrome; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Auriculo-Condylar Syndrome Diagnosed?

Auriculo-Condylar Syndrome is diagnosed on the basis of the following information:

  • Complete physical examination
  • Thorough medical history evaluation
  • Assessment of signs and symptoms
  • Laboratory tests
  • Imaging studies
  • Biopsy studies, if necessary

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 Auriculo-Condylar Syndrome?

The complications of Auriculo-Condylar Syndrome may include:

  • Feeding difficulties
  • Inadequate weight gain
  • Inability to thrive
  • Speech delay
  • Hearing loss

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

How is Auriculo-Condylar Syndrome Treated?

There is no cure for Auriculo-Condylar Syndrome, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that develops.

How can Auriculo-Condylar Syndrome be Prevented?

Auriculo-Condylar Syndrome may not be preventable, since it is a genetic disorder.

  • 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
  • Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
  • Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Auriculo-Condylar Syndrome? (Outcomes/Resolutions)

  • The prognosis of Auriculo-Condylar Syndrome is dependent upon the severity of the signs and symptoms and associated complications, if any
  • Individuals with mild conditions have better prognosis than those with severe symptoms and complications
  • Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Auriculo-Condylar Syndrome:

  • Auriculo-Condylar Syndrome is also known as Dysgnathia Complex

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


What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: April 30, 2018
Last updated: April 30, 2018