There is still some discussion on whether FND is sporadic or genetic. The majority of FND cases are sporadic. Yet, some studies describe families with multiple members with FND. Gene mutations are likely to play an important role in the cause. Unfortunately, the genetic cause for most types of FND remains undetermined.

Prognosis is poor. Previous research suggested a 100% mortality rate for those with acrania. This disease is rare, occurring in 1 in 20,000 live births.

In order to better manage an acrania diagnosis, early detection is of extreme importance so that actions may be taken to help the mother and child. Families may choose either to terminate the pregnancy, or to carry the child to term. Acrania may cause a fetus to spontaneously abort before reaching term.

OAFNS is a combination of FND and oculo-auriculo-vertebral spectrum (OAVS).

The diagnosis of OAVS is based on the following facial characteristics: microtia (underdeveloped external ear), preauricular tags, facial asymmetry, mandibular hypoplasia and epibulbar lipodermoids (benign tumor of the eye which consists of adipose and fibrous tissue).

There still remains discussion about the classification and the minimal amount of characteristics. When someone presents with FND and the characteristics of OAVS, the diagnosis OAFNS may be made.

As the incidence of OAFNS is unknown, there are probably a lot of children with mild phenotypes that aren’t being diagnosed as being OAFNS.

The cause of OAFNS is unknown, but there are some theories about the genesis. Autosomal recessive inheritance is suggested because of a case with two affected siblings and a case with consanguineous parents. However, another study shows that it is more plausible that OAFNS is sporadic.

It is known that maternal diabetes plays a role in developing malformations of craniofacial structures and in OAVS. Therefore, it is suggested as a cause of OAFNS. Folate deficiency is also suggested as possible mechanism.

Low-dose CT protocols should be considered in diagnosing children with OAFNS.

In a newborn boy thought to have Fryns syndrome, Clark and Fenner-Gonzales (1989) found mosaicism for a tandem duplication of 1q24-q31.2. They suggested that the gene for this disorder is located in that region. However, de Jong et al. (1989), Krassikoff and Sekhon (1990), and Dean et al. (1991) found possible Fryns syndrome associated with anomalies of chromosome 15, chromosome 6, chromosome 8(human)and chromosome 22, respectively. Thus, these cases may all represent mimics of the mendelian syndrome and have no significance as to the location of the gene for the recessive disorder.

By array CGH, Slavotinek et al. (2005) screened patients with DIH and additional phenotypic anomalies consistent with Fryns syndrome for cryptic chromosomal aberrations. They identified submicroscopic chromosome deletions in 3 probands who had previously been diagnosed with Fryns syndrome and had normal karyotyping with G-banded chromosome analysis. Two female infants were found to have microdeletions involving 15q26.2 (see 142340), and 1 male infant had a deletion in band 8p23.1 (see 222400).

Although no cause has been officially confirmed, researchers speculate the disease might result from a genetic mutation that sporadically occurs for unknown reasons.

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.

Several studies have reported that life expectancy appears to be normal for people with CCD.

Roberts syndrome is an extremely rare condition that only affects about 150 reported individuals. Although there have been only about 150 reported cases, the affected group is quite diverse and spread worldwide. Parental consanguinity (parents are closely related) is common with this genetic disorder. The frequency of Roberts syndrome carriers is unknown.

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).

Craniofacial abnormalities are congenital musculoskeletal disorders which primarily affect the cranium and facial bones.

They are associated with the development of the pharyngeal arches. Approximately, 5% of the UK or USA population present with dentofacial deformities requiring Orthognathic surgery, jaw surgery, and Orthodontics, brace therapy, as a part of their definitive treatment.

3C syndrome is very rare, occurring in less than 1 birth per million. Because of consanguinity due to a founder effect, it is much more common in a remote First Nations village in Manitoba, where 1 in 9 people carries the recessive gene.

It is usually autosomal dominant, but in some cases the cause is not known. It occurs due to haploinsufficiency caused by mutations in the CBFA1 gene (also called Runx2), located on the short arm of chromosome 6, which encodes transcription factor required for osteoblast differentiation. It results in delayed ossification of midline structures of the body, particularly membranous bone.

A new article reports that the CCD cause is thought to be due to a CBFA1 (core binding factor activity 1) gene defect on the short arm of chromosome 6p21 . CBFA1 is vital for differentiation of stem cells into osteoblasts, so any defect in this gene will cause defects in membranous and endochondral bone formation.

Till date about 18 cases of Spondylocostal dysostosis have been reported in literature.

In France, Aymé, "et al." (1989) estimated the prevalence of Fryns syndrome to be 0.7 per 10,000 births based on the diagnosis of 6 cases in a series of 112,276 consecutive births (live births and perinatal deaths).

The condition develops in the fetus at approximately 4 weeks gestational age, when some form of vascular problem such as blood clotting leads to insufficient blood supply to the face. This can be caused by physical trauma, though there is some evidence of it being hereditary . This restricts the developmental ability of that area of the face. Currently there are no definitive reasons for the development of the condition.

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.

Encephaloceles occur rarely, at a rate of one per 5,000 live births worldwide. Encephaloceles of the back of the head are more common in Europe and North America, while encephaloceles on the front of the head more frequently occur in Southeast Asia, Africa, Malaysia, and Russia. Ethnic, genetic, and environmental factors, as well as parental age, can all affect the likelihood of encephaloceles. The condition can occur in families with a family history of spina bifida.

Craniofrontonasal dysplasia is a very rare genetic condition. As such there is little information and no consensus in the published literature regarding the epidemiological statistics.

The incidence values that were reported ranged from 1:100,000 to 1:120,000.

Little genetic counseling can be offered for acrania because the genetic origins are not fully understood. In order to make genetic counseling for families easier this disease is often differentially diagnosed with other diseases that can occur at the same time such as anencephaly and acalvaria, though these diseases may not always occur simultaneously. While this disease is tragic, reoccurrence rates are extremely low so genetic counseling is not always necessary.

TCS occurs in about one in 50,000 births in Europe. Worldwide, it is estimated to occur in one in 10,000 to one in 50,000 births.

The disorder can be associated with a number of psychological symptoms, anxiety, depression, social phobia, body image disorders, and patients may be subjected to discrimination, bullying and name calling especially when young. A multi-disciplinary team and parental support should include these issues.

The reported incidence of constriction ring syndrome varies from 1/1200 and 1/15000 live births. The prevalence is equally in male and female.

Fetomaternal factors like prematurity, maternal illnes, low birth weight and maternal drug exposure are predisposing factors for the constriction ring syndrome.

No positive relationship between CRS and genetic inheritance has been reported.

Osteogenesis imperfecta is a rare condition in which bones break easily. There are multiple genetic mutations in different genes for collagen that may result in this condition. It can be treated with some drugs to promote bone growth, by surgically implanting metal rods in long bones to strengthen them, and through physical therapy and medical devices to improve mobility.

Babies born with Jarcho-Levin may be very healthy and grow up to lead normal lives. However, many individuals with Jarcho-Levin suffer from problems of respiratory insufficiency secondary to volume-restricted thoraces. These individuals will often develop pulmonary complications and die in infancy or early childhood. The disparity in outcomes of those with the syndrome is related to the fact that Jarcho-Levin actually encompasses two or more distinct syndromes, each with its own range of prognoses. The syndromes currently recognized as subtypes of Jarcho-Levin are termed spondylothoracic dysplasia and spondylocostal dysostosis. The disease is related to the SRRT gene.

Nager syndrome is thought to be caused by haploinsufficiency of the spliceosomal factor SF3B4.