Diagnosis is mostly clinical and radiological. Technetium skeletal scintigrams are occasionally used to determine number of exostoses.

Some parents of children with MHE have observed autism-like social problems in their children. To explore those observations more deeply, a 2012 study by the Sanford-Burnham Medical Research Institute used a mouse model of MHE to observe cognitive function. The findings indicated that the mutant mice endorsed three autistic characteristics: social impairment, impairments in ultrasonic vocalization, and repetitive behavior.

Diagnosis of Crouzon syndrome usually can occur at birth by assessing the signs and symptoms of the baby. Further analysis, including radiographs, magnetic resonance imaging (MRI) scans, genetic testing, X-rays and CT scans can be used to confirm the diagnosis of Crouzon syndrome.

Amniotic band syndrome is considered an accidental event and it does not appear to be genetic or hereditary, so the likelihood of it occurring in another pregnancy is remote. The cause of amnion tearing is unknown and as such there are no known preventative measures.

The key problem is the early fusion of the skull, which can be corrected by a series of surgical procedures, often within the first three months after birth. Later surgeries are necessary to correct respiratory and facial deformities.

Amniotic band syndrome is often difficult to detect before birth as the individual strands are small and hard to see on ultrasound. Often the bands are detected indirectly because of the constrictions and swelling upon limbs, digits, etc. Misdiagnosis is also common, so if there are any signs of amniotic bands, further detailed ultrasound tests should be done to assess the severity. 3D ultrasound and MRI can be used for more detailed and accurate diagnosis of bands and the resulting damage/danger to the fetus.

The diagnosis of this syndrome can be made on clinical examination and perinatal autopsy.

Koenig and Spranger (1986) noted that eye lesions are apparently nonobligatory components of the syndrome. The diagnosis of Fraser syndrome should be entertained in patients with a combination of acrofacial and urogenital malformations with or without cryptophthalmos. Thomas et al. (1986) also emphasized the occurrence of the cryptophthalmos syndrome without cryptophthalmos and proposed diagnostic criteria for Fraser syndrome. Major criteria consisted of cryptophthalmos, syndactyly, abnormal genitalia, and positive family history. Minor criteria were congenital malformation of the nose, ears, or larynx, cleft lip and/or palate, skeletal defects, umbilical hernia, renal agenesis, and mental retardation. Diagnosis was based on the presence of at least 2 major and 1 minor criteria, or 1 major and 4 minor criteria.

Boyd et al. (1988) suggested that prenatal diagnosis by ultrasound examination of eyes, digits, and kidneys should detect the severe form of the syndrome. Serville et al. (1989) demonstrated the feasibility of ultrasonographic diagnosis of the Fraser syndrome at 18 weeks' gestation. They suggested that the diagnosis could be made if 2 of the following signs are present: obstructive uropathy, microphthalmia, syndactyly, and oligohydramnios. Schauer et al. (1990) made the diagnosis at 18.5 weeks' gestation on the basis of sonography. Both the female fetus and the phenotypically normal father had a chromosome anomaly: inv(9)(p11q21). An earlier born infant had Fraser syndrome and the same chromosome 9 inversion.

Van Haelst et al. (2007) provided a revision of the diagnostic criteria for Fraser syndrome according to Thomas et al. (1986) through the addition of airway tract and urinary tract anomalies to the major criteria and removal of mental retardation and clefting as criteria. Major criteria included syndactyly, cryptophthalmos spectrum, urinary tract abnormalities, ambiguous genitalia, laryngeal and tracheal anomalies, and positive family history. Minor criteria included anorectal defects, dysplastic ears, skull ossification defects, umbilical abnormalities, and nasal anomalies. Cleft lip and/or palate, cardiac malformations, musculoskeletal anomalies, and mental retardation were considered uncommon. Van Haelst et al. (2007) suggested that the diagnosis of Fraser syndrome can be made if either 3 major criteria, or 2 major and 2 minor criteria, or 1 major and 3 minor criteria are present in a patient.

Children with Pfeiffer syndrome types 2 and 3 "have a higher risk for neurodevelopmental disorders and a reduced life expectancy" than children with Pfeiffer syndrome type 1, but if treated, favorable outcomes are possible. In severe cases, respiratory and neurological complications often lead to early death.

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.

There is no standard treatment for the hand malformations in Apert due to the differences and severity in clinical manifestations in different patients. Every patient should therefore be individually approached and treated, aiming at an adequate balance between hand functionality and aesthetics.

However, some guidelines can be given depending on the severity of the deformities.

In general it is initially recommended to release the first and fourth interdigital spaces, thus releasing the border rays.

This makes it possible for the child to grasp things by hand, a very important function for the child's development. Later the second and third interdigital spaces have to be released.

Because there are three handtypes in Apert, all with their own deformities, they all need a different approach regarding their treatment:

- Type I hand usually needs only the interdigital web space release. First web release is rarely needed but often its deepening is necessary. Thumb clynodactyly correction will be needed.

- In type II hands it is recommended to release the first and fifth rays in the beginning, then the second and the third interdigital web spaces have to be freed. The clynodactyly of the thumb has to be corrected as well. The lengthening of the thumb phalanx may be needed, thus increasing the first web space. In both type I and type II, the recurrent syndactyly of the second web space will occur because of a pseudoepiphysis at the base of the index metacarpal. This should be corrected by later revisions.

- Type III hands are the most challenging to treat because of their complexity. First of all, it is advised to release the first and fourth webspace, thus converting it to type I hand. The treatment of macerations and nail-bed infections should also be done in the beginning. For increasing of the first web space, lengthening of the thumb can be done. It is suggested that in severe cases an amputation of the index finger should be considered. However, before making this decision, it is important to weigh the potential improvement to be achieved against the possible psychological problems of the child later due to the aesthetics of the hand. Later, the second and/or third interdigital web space should be released.

With growing of a child and respectively the hands, secondary revisions are needed to treat the contractures and to improve the aesthetics.

The actual incidence of this disease is not known, but only 243 cases have been reported in the scientific literature, suggesting an incidence of on the order of one affected person in ten million people.

Lenz–Majewski syndrome is a skin condition characterized by hyperostosis, craniodiaphyseal dysplasia, dwarfism, cutis laxa, proximal symphalangism, syndactyly, brachydactyly, mental retardation, enamel hypoplasia, and hypertelorism.

In 2013, whole-exome sequencing showed that a missense mutation resulting in overactive phosphatidylserine synthase 1 was the cause of LMS, making it the first known human disease to be caused by disrupted phosphatidylserine metabolism. The researchers suggested a link between the condition and bone metabolism.

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.

Surgical correction is recommended when a constriction ring results in a limb contour deformity, with or without lymphedema.

The complete or partial absence of the pectoralis muscle is the malformation that defines Poland Syndrome. It can be treated by inserting a custom implant designed by CAD (computer aided design). A 3D reconstruction of the patient's chest is performed from a medical scanner to design a virtual implant perfectly adapted to the anatomy of each one. The implant is made of medical silicone unbreakable rubber. This treatment is purely cosmetic and does not make up for the patient's imbalanced upper body strength.

The Poland syndrome malformations being morphological, correction by custom implant is a first-line treatment. This technique allows a wide variety of patients to be treated with good outcomes. Poland Syndrome can be associated with bones, subcutaneous and mammary atrophy: if the first, as for pectus excavatum, is successfully corrected by a custom implant, the others can require surgical intervention such as lipofilling or silicone breast implant, in a second operation.

The timing of surgical interventions is debatable. Parents have to decide about their child in a very vulnerable time of their parenthood. Indications for early treatment are progressive deformities, such as syndactyly between index and thumb or transverse bones between the digital rays. Other surgical interventions are less urgent and can wait for 1 or 2 years.

Sclerosteosis is caused by mutations in the gene that encode for the sclerostin protein.

Surgical treatment of the cleft hand is based on several indications:

Improving function

- Absent thumb

- Deforming syndactyly (mostly between digits of unequal length like index and thumb)

- Transverse bones (this will progress the deformity; growth of these bones will widen the cleft)

- Narrowed first webspace

- The feet

Aesthetical aspects

- Reducing deformity

Sclerosteosis is an autosomal recessive disorder characterized by bone overgrowth. It was first described in 1958 but given the current name in 1967. Excessive bone formation is most prominent in the skull, mandible and tubular bones. It can cause facial distortion and syndactyly. Increased intracranial pressure can cause sudden death in patients. It is a rare disorder that is most prominent in the Afrikaner population in South Africa (40 patients), but there have also been cases of American and Brazilian families.

No surgical outcomes studies exist for evaluating the function of the thumbs after an on-top plasty reconstruction.

Webbed toes can be separated through surgery. Surgical separation of webbed toes is an example of body modification.

As with any form of surgery, there are risks of complications.

The end results depend on the extent of the webbing and underlying bone structure. There is usually some degree of scarring, and skin grafts may be required. In rare instances, nerve damage may lead to loss of feeling in the toes and a tingling sensation. There are also reports of partial web grow-back. The skin grafts needed to fill in the space between the toes can lead to additional scars in the places where the skin is removed.

Few clinical outcome studies exist regarding the treatment of central polydactyly. Tada and colleagues note that satisfactory surgical correction of central polydactyly is difficult to achieve and that outcomes are generally poor. In Tada’s study, 12 patients were reviewed. All patients required secondary surgical procedures to address flexion contractures and angular deviation at the IP joint level.

However, several primary factors contribute to the complexity of central polydactyly reconstruction. Hypoplastic joints and soft tissues that predispose the reconstructed finger to joint contracture, and angular deformities as well as complex tendon anomalies, are often difficult to address. Therefore, treatment is wholly dependent on the anatomic components present, the degree of syndactyly, and the function of the duplicated finger.

Synpolydactyly is a joint presentation of syndactyly (fusion of digits) and polydactyly (production of supernumerary digits). This is often a result of a mutation in the HOX D13 gene.

Types include:

The diagnosis of constriction ring syndrome can be confirmed with an ultrasonography. The clinical manifestations can be extremely variable. It could be a single or multiple manifestation. This can be confirmed at the end of the first trimester or at the beginning of the second trimester. But not every patient will be diagnosed at that moment, most will get this diagnosis at birth.

Acrocephalosyndactylia (or acrocephalosyndactyly) is the common presentation of craniosynostosis and syndactyly.