Auriculocondylar Syndrome: Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Human birth defect syndromes are usually present from birth, and the malformations affecting the face are most common among them. Auriculocondylar syndrome is one such syndrome in patients with a malformed ear and mandible (lower jaw). It is a rare genetic disorder that is characterized by developmental abnormalities of the face. People with auriculocondylar syndrome usually have malformed external ears. The affected structures are those which originated from the neural crest cells. These cells are present in the pharyngeal arches of the embryo and give rise to most of the bones, cartilage, and connective tissue of the face. The genetic mutation leads to developmental issues in these cells during the embryo stage leading to this syndrome.

What Is Auriculocondylar Syndrome?

Auriculocondylar syndrome (auriculo - refers to the ears), also known as question-mark ear syndrome, is a genetic condition present at birth. It gives a question-mark appearance to the router ear therefore, the name question-mark ear syndrome. This appearance usually occurs due to the split between the upper part of the ear and the earlobe. Moreover, other ear abnormalities, such as narrow ear canals or, in rare cases, hearing loss, might also occur.

Other names of auriculocondylar syndrome include -

• Auriculo-condylar syndrome.

• Dysgnathia complex.

• Question-mark ear syndrome.

Is Auriculocondylar Syndrome Congenital?

According to various research, it is a very rare condition that has been found in around 1000 people around the world. This syndrome is usually present at birth and has a genetic autosomal dominant pattern, which means that this condition can be passed down from parent to child or occur due to a mutation change in a gene. However, an affected individual has a 50 percent chance of passing this syndrome to a future child.

This syndrome can affect both males and females equally and without any racial or ethnic group preference.

What Genes Are Responsible for Auriculocondylar Syndrome?

Genetic mutation in any of the following genes can lead to auriculocondylar syndrome, which includes GNAI3 or PLCB4. These genes make proteins that help in chemical signaling within cells. They help transmit information from outside to the inside of the cell, which helps them grow, divide and perform specialized functions.

Moreover, various studies have also suggested that the proteins produced from these genes also help develop the first and second pharyngeal arches present in the embryo that develop into jawbones, middle ear bones, ear canals, outer ears, and facial muscles. Therefore the mutations in genes alter the formation of the lower jaw and ears. The mandible shape gets altered to the upper jaw, which is smaller, leading to problems with TMJ (temporomandibular joint) functioning.

Additionally, in some cases where the mutation in GNAI3 or PLCB4 has not been found, the actual cause of this syndrome remains unknown.

What Are the Clinical Features of Auriculocondylar Syndrome?

Patients with auriculocondylar syndrome usually have malformed outer ears, and the common characteristic feature of this condition is a question-mark shape ear.

Ear Abnormalities Include-

• Cupped ears.

• Ears with fewer folds and grooves.

• Narrow ear canals.

• Small skin tags in front or behind the ears.

• Backward rotated ears.

• Low-set ears.

Craniofacial Involvement-

The craniofacial abnormalities are characterized by-

• Bilateral external ear malformations.

• Mandibular condyle hypoplasia.

• Microstomia (small size mouth).

• Facial asymmetry.

Additional manifestations include

• Hypotonia (decreased muscle tone).

• Ptosis (drooping of upper eyelids).

• Cleft palate.

• Developmental delay.

• Hearing impairment.

• Respiratory distress.

• Snoring.

Mandible Related Abnormalities -

The abnormalities of the mandible (lower jaw) are another characteristic feature of auriculocondylar syndrome, which includes-

• Unusually small chin (micrognathia).

• Micro-glossia (small size tongue).

• Abnormal functioning of the temporomandibular joint (TMJ).

• Problems with the TMJ that affects the closing and opening of the mouth.

Other oral cavity-related abnormalities include -

• Anterior open-bite malocclusion.

• Chewing difficulties.

• Dental crowding.

• Dental malocclusion.

• Speech articulation difficulties.

All these features vary, even among affected members of the same family.

How Is Auriculocondylar Syndrome Diagnosed?

Auriculocondylar syndrome can be diagnosed by conducting various tests, such as a complete physical examination and thorough medical history evaluation. As this condition affects multiple parts, the test must be conducted according to the part affected. Most clinical conditions may have similar signs and symptoms, and the healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

However, on radiographic examination, various findings can be seen, which include the following-

On CT (computed tomography) and MRI (magnetic resonance imaging), mandible and ear abnormalities can be seen, such as -

• Ear scans show a prominent malformed ear and auricular cleft (question mark ear).

• Mandibular scans shows Mandibular condyle aplasia or hypoplasia.

• Glenoid hypoplasia.

• Micrognathia.

• Short mandibular rami.

• Small coronoid processes.

• Poorly formed temporomandibular joint.

Auriculocondylar syndrome is a genetic disorder, and therefore, it cannot be prevented. Therefore genetic testing and prenatal diagnosis (molecular testing of the fetus during pregnancy) of the expected parents can help find this condition in the embryo stage of the child. This can help greatly in understanding the condition and complications related to it.

In case of a family history of auriculocondylar syndrome, genetic counseling may help assess the risks and also helps in family planning, as the child can get this disease from the affected parent.

There is still research going on for the treatment and prevention of inherited and acquired genetic disorders.

What Are the Complications of Auriculo-Condylar Syndrome?

The complications of Auriculo-Condylar Syndrome may include:

• Feeding difficulties.

• Inadequate weight gain.

• Speech delay.

• Inability to thrive.

• Hearing loss.

How Is Auriculocondylar Syndrome Treated?

There is no cure for auriculocondylar syndrome since it is a genetic condition. However, the treatment usually focuses on managing the signs and symptoms involved in this condition and its complications.

What Is the Prognosis of Auriculocondylar Syndrome?

The prognosis of auriculocondylar syndrome depends upon the severity of the signs and symptoms and associated complications. Patients with mild to moderate signs and symptoms have a better prognosis than those with severe symptoms. And there is no way the severity levels of the symptoms and complications can be assessed, and it varies from case to case.

Conclusion:

Auriculocondylar syndrome is a very rare condition and is not life-threatening. However, the symptoms or complications associated with it can disrupt the life of the patient. Parents with a family history of this condition should be aware and consult a medical professional in case they are family planning to understand how to cope with this disease.