Courses of treatment typically include the following:

- Draining the pus once awhile as it can build up a strong odor

- Antibiotics when infection occurs.

- Surgical excision is indicated with recurrent fistular infections, preferably after significant healing of the infection. In case of a persistent infection, infection drainage is performed during the excision operation. The operation is generally performed by an appropriately trained specialist surgeon e.g. an otolaryngologist or a specialist General Surgeon.

- The fistula can be excised as a cosmetic operation even though no infection appeared. The procedure is considered an elective operation in the absence of any associated complications.

The prevalence has been estimated at 1 in 10,000 births, but exact values are hard to know because some that have the symptoms rarely have Pierre-Robin sequence (without any other associated malformation).

Occasionally a preauricular sinus or cyst can become infected.

Most preauricular sinuses are asymptomatic, and remain untreated unless they become infected too often. Preauricular sinuses can be excised with surgery which, because of their close proximity to the facial nerve, is performed by an appropriately trained, experienced surgeon (e.g. a specialist General Surgeon, a Plastic Surgeon, an otolaryngologist (Ear, Nose, Throat surgeon) or an Oral and Maxillofacial Surgeon).

There has been a great deal of research to understand the cause of PHACE Syndrome. The abnormalities associated with this syndrome are thought to be due to errors that occur very early during development. Unfortunately, why the errors occur, or the exact cause is still unknown. PHACE has a shared biology of other vascular anomalies. There may be a genetic component involved and studies are underway to investigate this idea. No familial cases have been identified to date. Research is ongoing to find the cause of all vascular anomalies including PHACE Syndrome.

In disease states, maxillary prognathism is associated with Cornelia de Lange syndrome; however, so-called false maxillary prognathism, or more accurately, retrognathism, where there is a lack of growth of the mandible, is by far a more common condition.

Prognathism, if not extremely severe, can be treated in growing patients with orthodontic functional or orthopaedic appliances. In adult patients this condition can be corrected by means of a combined surgical/orthodontic treatment, where most of the time a mandibular advancement is performed. The same can be said for mandibular prognathism.

Surgery is needed to prevent the closing of the coronal sutures from damaging brain development. In particular, surgeries for the LeFort III or monobloc midface distraction osteogenesis which detaches the midface or the entire upper face, respectively, from the rest of the skull, are performed in order to reposition them in the correct plane. These surgeries are performed by both plastic and oral and maxillofacial (OMS) surgeons, often in collaboration.

OAF is a complication of oroantral communication. Other complications may arise if left untreated. For example:

- Candidal infection

- Chronic maxillary sinus infection of bacterial origin

- Osteomyelitis

- Rhinosinusitis

- Sinus pathology

Therefore, OAF should be dealt with first, before treating the complications.

Not all alveolar prognathism is anomalous, and significant differences can be observed among different ethnic groups.

Harmful habits such as thumb sucking or tongue thrusting can result in or exaggerate an alveolar prognathism, causing teeth to misalign. Functional appliances can be used in growing children to help modify bad habits and neuro-muscular function, with the aim of correcting this condition.

Alveolar prognathism can also easily be corrected with fixed orthodontic therapy. However, relapse is quite common, unless the cause is removed or a long-term retention is used.

Amelogenesis imperfecta hypomaturation type with taurodontism are often confused. Amelogenesis imperfecta of the hypomaturation type with taurodontism (AIHHT) has no hair or bone changes which helps to differentiate between TDO cases and AIHHT. Polymerase chain reaction also known as PCR is used to amply pieces of DNA and observed for the 141 base pair allele as a result of a deletion of four nucleotides in exon 3 of the DLX-3 gene. Additionally, the current research shows that there is heavy reliance on the physical characteristics in the differentiation of TDO verses AIHHT and the severity and prevalence of their expression. For instance, taurodontism is severely expressed in TDO, but mildly expressed in AIHHT. Currently, researchers are trying to identify the reason for the alteration in the DLX-3 and DLX-7 genes that are responsible for AIHHT versus TDO.

Schimmelpenning syndrome appears to be sporadic rather than inherited, in almost all cases. It is thought to result from genetic mosaicism, possibly an autosomal dominant mutation arising after conception and present only in a subpopulation of cells. The earlier in embryological development such a mutation occurs, the more extensive the nevi are likely to be and the greater the likelihood of other organ system involvement.

Tooth pathology (or tooth diseases, tooth disorders or dental pathology), is any condition of the teeth that can be congenital or acquired. Sometimes a congenital tooth diseases are called "tooth abnormalities". These are among the most common diseases in humans The prevention, diagnosis, treatment and rehabilitation of these diseases are the base to the dentistry profession, in which are dentists and dental hygienists, and its sub-specialties, such as oral medicine, oral and maxillofacial surgery, and endodontics.

Studies have shown that sinusitis is found in about 60% of the cases on the fourth day after the manifestation of sinus. Moreover, patient may be afflicted with an acute sinus disease if OAC is not treated promptly upon detecting clear signs of sinusitis. So, early diagnosis of OAC must be conducted in order to prevent OAF from setting in.

Spontaneous healing of small perforation is expected to begin about 48 hours after tooth extraction and it remains possible during the following two weeks. Patient must consult the dentist as early as possible should a large defect of more than 7mm in diameter or a dogged opening that requires closure is discovered so that appropriate and suitable treatment can be swiftly arranged or referral to Oral Maxillofacial Surgery (OMFS) be made at the local hospital, if required.

A comprehensive preoperative radiographic evaluation is a must as the risk of OAC can increase due to one or more of the following situations :-

- Close relationship between the roots of the maxillary posterior teeth and the sinus floor

- Increased divergence or dilaceration of the roots of the tooth

- Marked pneumatization of the sinus leading to a larger size

- Peri-radicular lesions involving teeth or roots in close association with the sinus floor

Hence, in such cases:

- Avoid using too much of apical pressure during tooth extraction

- Perform surgical extraction with roots sectioning

- Consider referral to OMFS at local hospital

Omphalocele has been described in two patients with Apert syndrome by Herman T.E. et al. (USA, 2010) and by Ercoli G. et al. (Argentina, 2014). An omphalocele is a birth defect in which an intestine or other abdominal organs are outside of the body of an infant because of a hole in the bellybutton area. However, the association between omphalocele and Apert syndrome is not confirmed yet, so additional studies are necessary.

PHACE Syndrome is the uncommon association between large infantile hemangiomas, usually of the face, and birth defects of the brain, heart, eyes, skin and/or arteries. It is an acronym that stands for the medical names of the parts of the body it often impacts:

- Posterior fossa abnormalities and other structural brain abnormalities

- Hemangioma(s) of the cervical facial region

- Arterial cerebrovascular anomalies

- Cardiac defects, aortic coarctation and other aortic abnormalities

- Eye anomalies

Sometimes an "S" is added to PHACE making the acronym PHACES; with the "S" standing for "Sternal defects" and/or "Supraumbilical raphe."

In 1993, an association between large facial hemangiomas and brain defects among 9 subjects was reported. 3 years later, a larger case study was published showing a wider spectrum of grouped malformations. The association of anomalies and the PHACES acronym was first coined by Dr. Vail Reese and Dr. Ilona Frieden in 1996, making it a newly described syndrome. A diagnosis is generally made from the physical examination, along with imaging of the head and chest, and an eye examination. PHACE is most commonly diagnosed among female infants. Long-term quality of life varies.

Hemangioma growth phase can last anywhere from 6 to 18 months. Then involution, or healing, of the hemangioma begins. Laser and other surgeries usually are able to make a substantial positive impact on appearance. Long after the hemangioma recedes, any damage it or the other defects caused, may remain. Migraines are common, as are developmental delays.

A single copy of the abnormal gene from one parent is able to cause the disease; this is called autosomal dominance. A mutation in the DLX3 gene has been confirmed as the cause of TDO. The onset of TDO begins with a 4 base pair deletion on chromosome 17q21, causing a mutation, specifically frameshift, and the termination codon to be the cause of the lack of complete maturation of the tooth enamel; this mutation is also responsible for the osseous defects in the bone. DLX-3 is expressed in the placenta and is significantly important during embryonic development in regards to hard bone tissue which is present in the teeth, skull, and long bones such as in the arms and legs. During normal tooth development, DLX 3 shifts from predominant expression in the inner enamel epithelium; the outer layer does not express DLX 3. In TDO cases, the DLX-3 is present on the outer enamel epithelium and leads to the dental abnormalities seen in this disease. Improper expression of DLX-3 causes the tooth enamel to be thinner, which leads to attrition and is most often the cause of dental abscess seen in TDO persons.

During osseous, connective tissue, and dermal cell differentiation, DLX 3 in TDO is also responsible for upper cranial thickness, calvaria, osteosclerosis of the long bones, long narrow head (dolichocephaly), abnormally thin brittle nails, and premature closing of fibrous joints. Consequently, 95% of people with TDO that are 16 years old or younger show skeletal abnormalities before full maturation takes place. Lack of mastoid pneumatization by mastoid cells occurs in 82% of the cases and is rarely prevalent outside of TDO diagnosis. Mastoid pneumatization occurs at about 6 months of ages and acts to minimize pressure fluctuations in the Eustachian tubes of the ear. The mastoid lies posterior to the lower jawbone (mandible) and distal to the ear. The Eustachian tube connects the middle ear to the back of the nose, and acts to create a specific pressure in the ear canal that causes vibrations to the eardrum; if adequate pressure is not attained, muffled, dull hearing results. In addition to the mastoid pneumatization assisting the Eustachian tubes for normal hearing, lack of mastoid pneumatization causes inflammation of the ear, general irritation, and does not allow enough air in to assist with mucus flowing out. It is not completely understood why gene mutations occur, but it is known that genetic mutations that cause disease are acquired from either or both parents at fertilization.

It is not known how this abnormality occurs in infants, but one theory is that, at some time during the stage of the formation of the bones of the fetus, the tip of the jaw (mandible) becomes 'stuck' in the point where each of the collar bones (clavicle) meet (the sternum), effectively preventing the jaw bones from growing. It is thought that, at about 12 to 14 weeks gestation, when the fetus begins to move, the movement of the head causes the jaw to "pop out' of the collar bones. From this time on, the jaw of the fetus grows as it would normally, with the result that, when born, the jaw of the baby is much smaller (micrognathia) than it would have been with normal development, although it does continue to grow at a normal rate until the child reaches maturity.

However, association with gene loci 2q24.1-33.3, 4q32-qter, 11q21-23.1, and 17q21-24.3 has been found. Recent studies have indicated that genetic dysregulation of SOX9 gene prevents the SOX9 protein from properly controlling the development of facial structures, which leads to isolated PRS. Similarly, KCNJ2 gene also has a role to play. Overlap with certain other genetic syndromes like Patau syndrome has also been found.

PRS may occur in isolation, but it is often part of an underlying disorder or syndrome. The most common is Stickler Syndrome. Other disorders causing PRS, according to Dr. Robert J. Sphrintzen Ph.D. of the Center for Craniofacial Disorders Montefiore Medical Center, are Velocardiofacial syndrome, Fetal Alcohol Syndrome and Treacher Collins Syndrome. For more disorders associated with PRS see Dr. Sphrintzen's article entitled "The Implications of the Diagnosis of Robin Sequence".

Medical conditions include frequent ear infection, hearing loss, hypotonia, developmental problems, respiratory problems, eating difficulties, light sensitivity, and esophageal reflux.

Data on fertility and the development of secondary sex characteristics is relatively sparse. It has been reported that both male and female patients have had children. Males who have reproduced have all had the autosomal dominant form of the disorder; the fertility of those with the recessive variant is unknown.

Researchers have also reported abnormalities in the renal tract of affected patients. Hydronephrosis is a relatively common condition, and researchers have theorized that this may lead to urinary tract infections. In addition, a number of patients have suffered from cystic dysplasia of the kidney.

A number of other conditions are often associated with Robinow syndrome. About 15% of reported patients suffer from congenital heart defects. Though there is no clear pattern, the most common conditions include pulmonary stenosis and atresia. In addition, though intelligence is generally normal, around 15% of patients show developmental delays.

Incidence of Crouzon syndrome is currently estimated to occur in 1.6 out of every 100,000 people. There is a greater frequency in families with a history of the disorder, but that doesn't mean that everyone in the family is affected (as referred to above).

When a patient has multiple abnormalities (multiple anomaly, multiple deformity), they have a congenital abnormality that can not be primarily identified with a single system of the body or single disease process. Most medical conditions can have systemic sequelae, but multiple abnormalities occur when the effects on multiple systems is immediately obvious.

Genetic studies have linked the autosomal recessive form of the disorder to the "ROR2" gene on position 9 of the long arm of chromosome 9. The gene is responsible for aspects of bone and cartilage growth. This same gene is involved in causing autosomal dominant brachydactyly B.

The autosomal dominant form has been linked to three genes - WNT5A, Segment polarity protein dishevelled homolog DVL-1 (DVL1) and Segment polarity protein dishevelled homolog DVL-3 (DVL3). This form is often caused by new mutations and is generally less severe then the recessive form. Two further genes have been linked to this disorder - Frizzled-2 (FZD2) and Nucleoredoxin (NXN gene). All of these genes belong to the same metabolic pathway - the WNT system. This system is involved in secretion for various compounds both in the fetus and in the adult.

A fetal ultrasound can offer prenatal diagnosis 19 weeks into pregnancy. However, the characteristics of a fetus suffering from the milder dominant form may not always be easy to differentiate from a more serious recessive case. Genetic counseling is an option given the availability of a family history.

In general, children with a small isolated nevus and a normal physical exam do not need further testing; treatment may include potential surgical removal of the nevus. If syndrome issues are suspected, neurological, ocular, and skeletal exams are important. Laboratory investigations may include serum and urine calcium and phosphate, and possibly liver and renal function tests. The choice of imaging studies depends on the suspected abnormalities and might include skeletal survey, CT scan of the head, MRI, and/or EEG.

Depending on the systems involved, an individual with Schimmelpenning syndrome may need to see an interdisciplinary team of specialists: dermatologist, neurologist, ophthalmologist, orthopedic surgeon, oral surgeon, plastic surgeon, psychologist.

In utero exposure to cocaine and other street drugs can lead to agenesis of corpus callosum.

Other factors such as toxicants can adversely impact bone cells. Infections, chronic or acute, can affect blood flow by inducing platelet activation and aggregation, contributing to a localized state of excess coagulability (hypercoagulability) that may contribute to clot formation (thrombosis), a known cause of bone infarct and ischaemia. Exogenous estrogens, also called hormonal disruptors, have been linked with an increased tendency to clot (thrombophilia) and impaired bone healing.

Heavy metals such as lead and cadmium have been implicated in osteoporosis. Cadmium and lead promotes the synthesis of plasminogen activator inhibitor-1 (PAI-1) which is the major inhibitor of fibrinolysis (the mechanism by which the body breaks down clots) and shown to be a cause of hypofibrinolysis. Persistent blood clots can lead to congestive blood flow (hyperemia) in bone marrow, impaired blood flow and ischaemia in bone tissue resulting in lack of oxygen (hypoxia), bone cell damage and eventual cell death (apoptosis). Of significance is the fact that the average concentration of cadmium in human bones in the 20th century has increased to about 10 times above the pre-industrial level.

The disease is associated with high morbidity and mortality and mainly affects children under the age of twelve in the poorest countries of Africa. Children in Asia and some countries of South America are also affected. Most children who get the disease are between the ages of two and six years old. The WHO estimates that 500,000 people are affected, and that 140,000 new cases are reported each year. The mortality rate is approximately 90 percent.

Each child is different and it entirely depends on which sutures are fused and how it is affecting the child as to how it is treated. Some children have severe breathing issues due to shallow mid face and may require a tracheostomy. All should be treated at a specialist centre. Cranio bands are not used in the UK.

Surgery is typically used to prevent the closure of sutures of the skull from damaging the brain's development. Without surgery, blindness and mental retardation are typical outcomes. Craniofacial surgery is a discipline of both plastic surgery and oral and maxillofacial surgery (OMFS) . To move the orbits forward, craniofacial surgeons expose the skull and orbits and reshape the bone. To treat the midface deficiency, craniofacial surgeons can move the lower orbit and midface bones forward. For jaw surgery, either plastic surgeons or OMFS surgeons can perform these operations.

Crouzon patients tend to have multiple sutures involved, most specifically bilateral coronal craniosynostoses, and either open vault surgery or strip craniectomy (if child is under 6 months) can be performed. In the later scenario, a helmet is worn for several months following surgery.

Once treated for the cranial vault symptoms, Crouzon patients generally go on to live a normal lifespan.