The cause of Primrose syndrome is currently unknown. This condition is extremely rare and seems to spontaneously occur, regardless of family history.

In the case studied by Dalai et al. in 2010, it was found that an abnormally high amount of calcitonin, a hormone secreted by the thyroid gland to stabilize blood calcium levels, was present in the blood serum. This suggests that the thyroid gland is releasing an abnormal amount of calcitonin, resulting in the disruption of calcium level homeostasis. No molecular cause was found, but an expanded microarray analysis of the patient found a 225.5 kb deletion on chromosome 11p between rs12275693 and rs1442927. Whether or not this deletion is related to the syndrome or is a harmless mutation is unknown. The deletion was not present in the patient's mother's DNA sample, but the father's DNA was unavailable.

Möbius syndrome results from the underdevelopment of the VI and VII cranial nerves. The VI cranial nerve controls lateral eye movement, and the VII cranial nerve controls facial expression.

The causes of Möbius syndrome are poorly understood. Möbius syndrome is thought to result from a vascular disruption (temporary loss of bloodflow) in the brain during prenatal development. There could be many reasons that a vascular disruption leading to Möbius syndrome might occur. Most cases do not appear to be genetic. However, genetic links have been found in a few families. Some maternal trauma may result in impaired or interrupted blood flow (ischemia) or lack of oxygen (hypoxia) to a developing fetus. Some cases are associated with reciprocal translocation between chromosomes or maternal illness. In the majority of cases of Möbius syndrome in which autosomal dominant inheritance is suspected, sixth and seventh cranial nerve paralysis (palsy) occurs without associated limb abnormalities.

The use of drugs and a traumatic pregnancy may also be linked to the development of Möbius syndrome. The use of the drugs misoprostol or thalidomide by women during pregnancy has been linked to the development of Möbius syndrome in some cases. Misoprostol is used to induce abortions in Brazil and Argentina as well as in the United States. Misoprostol abortions are successful 90% of the time, meaning that 10% of the time the pregnancy continues. Studies show that the use of misoprostal during pregnancy increases the risk of developing Möbius syndrome by a factor of 30. While this is a dramatic increase in risk, the incidence of Möbius syndrome without misoprostal use is estimated at one in 50000 to 100000 births (making the incidence of Möbius syndrome with misoprostol use, less than one in 1000 births). The use of cocaine (which also has vascular effects) has been implicated in Möbius syndrome.

Some researchers have suggested that the underlying problem of this disorder could be congenital hypoplasia or agenesis of the cranial nerve nuclei. Certain symptoms associated with Möbius syndrome may be caused by incomplete development of facial nerves, other cranial nerves, and other parts of the central nervous system.

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.

The common symptoms in all reported cases of primrose syndrome include ossified pinnae, learning disabilities or mental retardation, hearing problems, movement disorders (ataxia, paralysis, and parkinsonism among others (likely due, in part, to calcification of the basal ganglia), a torus palatinus (a neoplasm on the mouth's hard palate), muscle atrophy, and distorted facial features. Other symptoms usually occur, different in each case, but it is unknown whether or not these symptoms are caused by the same disease.

Fountain syndrome is an autosomal recessive congenital disorder characterized by mental retardation, deafness, skeletal abnormalities and a coarse face with full lips. The abnormal swelling of the cheeks and lips are due to the excessive accumulation of body fluids under the skin. The deafness is due to malformation of the cochlea structure within the inner ear.

The frequency is unknown, but the disease is considered to be very rare.

Unfortunately, there is not one specific treatment option that can rid a person of this syndrome. However, there are many routes one can take to make living with this disease a lot easier. For example, there are many treatment programs that doctors can specialize for patients and their needs. Meeting with a doctor is very crucial and these specializations can be very useful. Also, one can seek help from pediatricians, EENT doctors, audiologists, and orthopedists. Brace fittings, hearing aids, and physical therapy can also be pushed by one's doctor, so that a patient can live normally. Additionally, anticonvulsant drugs can be used to stop seizures.

After the last primary tooth is lost, usually around the age of twelve, final orthodontic treatment can be initiated. A patient that has not been able to close or swallow well probably will have an open bite, deficient lower-jaw growth, a narrow archform with crowded teeth, and upper anterior flaring of teeth. Orthognathic (jaw) surgery may be indicated. This should be completed in most situations before the smile surgery where the gracilis muscle is grafted to the face.

Genetic links to 13q12.2 and 1p22 have been suggested.

Weissenbacher-Zweymüller syndrome affects males and females in the same numbers. About 30 cases have been reported in medical literature. This disorder can be underdiagnosed causing no true frequency in the population. Only 30 cases have been reported in medical literature.

As its name indicates, a person with the syndrome has one Y chromosome and four X chromosomes on the 23rd pair, thus having 49 chromosomes rather than the normal 46. As with most categories of aneuploidy disorders, 49,XXXXY syndrome is often accompanied by intellectual disability. It can be considered a form of 47, XXY Klinefelter syndrome, or a variant of it.

It is genetic but not hereditary. This means that while the genes of the parents cause the syndrome, there is a small chance of more than one child having the syndrome. The probability of inheriting the disease is about 1%.

The individuals with this syndrome are males, but 49, XXXXX also exists with similar characteristics.

Respiratory complications are often cause of death in early infancy.

Marshall–Smith syndrome is not to be confused with:

- Marshall syndrome (aka.Periodic fever, aphthous stomatitis, pharyngitis and adenitis (PFAPA syndrome, see also: Periodic fever syndrome)

- Sotos (like) syndrome

- Weaver-Smith syndrome (WSS)

Presence of inner ear abnormalities lead to Delayed gross development of child because of balance impairment and profound deafness which increases the risk of trauma and accidents.

- Incidence of accidents can be decreased by using visual or vibrotactile alarm systems in homes as well as in schools.

- Anticipatory education of parents, health providers and educational programs about hazards can help.

Dominant genetic disorders can be caused by just a single copy of an abnormal gene. This abnormal gene can be the result of being inherited from either parent or be a new mutation. Most cases are caused by a de novo (new) mutation in the gene that occurs during the formation of the egg or sperm. These cases occur when there is no history of the disorder in the family.

The COL11A2 gene is responsible for providing instructions on making one component of the type XI collagen. Type XI collagen is a complex molecule that helps give structure and strength to the connective tissues. Collagen is found in bone. It is also found in cartilage that makes up most of the skeleton during early development. The mutation of COL11A2 in Weissenbacher-Zweymüller syndrome disrupts the assembly of the type XI collagen molecules. The malfunctioning collagen weakens the connective tissue causing impaired bone development.

COL11A2 is also associated with autosomal dominant non-syndromic hearing loss (ADNSHL). All mutations of COL11A2 in ADNSHL are missense mutations.

Michel aplasia, also known as complete labyrinthine aplasia (CLA), is a congenital abnormality of the inner ear. It is characterized by the bilateral absence of differentiated inner ear structures and results in complete deafness (anacusis).

Michel aplasia should not be confused with michel dysplasia. It may affect one or both ears.

"Aplasia" is the medical term for body parts that are absent or do not develop properly. In Michel aplasia, the undeveloped (anaplastic) body part is the bony labyrinth of the inner ear. Other nearby structures may be underdeveloped as well.

Recent research has been focused on studying large series of cases of 3-M syndrome to allow scientists to obtain more information behind the genes involved in the development of this disorder. Knowing more about the underlying mechanism can reveal new possibilities for treatment and prevention of genetic disorders like 3-M syndrome.

- One study looks at 33 cases of 3M syndrome, 23 of these cases were identified as CUL7 mutations: 12 being homozygotes and 11 being heterozygotes. This new research shows genetic heterogeneity in 3M syndrome, in contrast to the clinical homogeneity. Additional studies are still ongoing and will lead to the understanding of this new information.

- This study provides more insight on the three genes involved in 3M syndrome and how they interact with each other in normal development. It lead to the discovery that the CUL7, OBS1, and CCDC8 form a complex that functions to maintain microtubule and genomic integrity.

3-M syndrome is most often caused by a mutation in the gene CUL7, but can also be seen with mutations in the genes OBS1 and CCDC8 at lower frequencies. This is an inheritable disorder and can be passed down from parent to offspring in an autosomal recessive pattern. An individual must receive two copies of the mutated gene, one from each parent, in order to be have 3-M syndrome. An individual can be a carrier for the disorder if they inherit only one mutant copy of the gene, but will not present any of the symptoms associated with the disorder.

Since 3-M syndrome is a genetic condition there are no known methods to preventing this disorder. However, genetic testing on expecting parents and prenatal testing, which is a molecular test that screens for any problems in the heath of a fetus during pregnancy, may be available for families with a history of this disorder to determine the fetus' risk in inheriting this genetic disorder.

ODD is typically an autosomal dominant condition, but can be inherited as a recessive trait. It is generally believed to be caused by a mutation in the gene GJA1, which codes for the gap junction protein connexin 43. Slightly different mutations in this gene may explain the different way the condition manifests in different families. Most people inherit this condition from one of their parents, but new cases do arise through novel mutations. The mutation has high penetrance and variable expression, which means that nearly all people with the gene show signs of the condition, but these signs can range from very mild to very obvious.

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.

One family of 68 individuals over 5 generations was studied and the prevalence of disease among the family members suggests that it is indicative of dominant inheritance that is not sexually linked. This is supported by the fact that the disease failed to skip generations even in the absence of intermarriages and that disease incidence was independent of sex. The current findings suggest that the cause of the disease could be narrowed down to one enzymatic defect that is involved in the development of neuroectodermal tissue, however the exact molecular mechanisms are currently unknown. The other symptoms that arise such as bone defects and diabetes may be secondary to this enzymatic defect.

Many people with MDP syndrome are high achievers intellectually following careers in law, medicine and computing. A crucial point is that they do not have progeria and there is no evidence of accelerated intellectual decline with age in these patients. Equally life expectancy has not been shown to be reduced. Patients of 65 have been described in the literature and none of the patients are known to have malignancy. Therefore, there are many crucial differences with progeria and the name of progeroid in the title is confusing as this really refers to the lack of fat in the face and taut skin and not any intellectual or other age associated features.

Bangstad syndrome is a severe, inherited congenital disorder associated with abnormalities of the cell membrane.

It was characterized in 1989.

Mondini dysplasia, also known as Mondini malformation and Mondini defect, is an abnormality of the inner ear that is associated with sensorineural hearing loss.

This deformity was first described in 1791 by Mondini after examining the inner ear of a deaf boy. The Mondini dysplasia describes a cochlea with incomplete partitioning and a reduced number of turns, an enlarged vestibular aqueduct and a dilated vestibule. A normal cochlea has two and a half turns, a cochlea with Mondini dysplasia has one and a half turns; the basal turns being normally formed with a dilated or cystic apical turn to the cochlear. The hearing loss can deteriorate over time either gradually or in a step-wise fashion, or may be profound from birth.

Hearing loss associated with Mondini dysplasia may first become manifest in childhood or early adult life. Some children may pass newborn hearing screen to lose hearing in infancy but others present with a hearing loss at birth. Hearing loss is often progressive and because of the associated widened vestibular aqueduct may progress in a step-wise fashion associated with minor head trauma. Vestibular function is also often affected. While the hearing loss is sensorineural a conductive element may exist probably because of the third window effect of the widened vestibular aqueduct. The Mondini dysplasia can occur in cases of Pendred Syndrome and Branchio-oto-renal syndrome and in other syndromes, but can occur in non-syndromic deafness.

Campomelic dysplasia has a reported incidence of 0.05-0.09 per 10000 live births.

In nearly 95% of the cases, death occurs in the neonatal period due to respiratory distress, generally related to small chest size or insufficient development of the trachea and other upper airway structures.

Among survivors of CMD, the skeletal malformations change over time to include worsening scoliosis or kyphosis resulting in decreased trunk size relative to the limb length. Neurological damage is also often seen including mental retardation and deafness. Even among survivors of the prenatal period, CMD patients have shortened life spans due to lifelong respiratory issues. Those patients with ambiguous genitalia or sex reversal at birth, of course, maintain that state, and are either sterile or have reduced fertility.

Weaver syndrome (also called Weaver-Smith syndrome) is an extremely rare congenital disorder associated with rapid growth beginning in the prenatal period and continuing through the toddler and youth years. It is characterized by advanced osseous maturation, and distinctive craniofacial, skeletal, and neurological abnormalities. It was first described by Dr. David Weaver in 1974. It is similar to Sotos syndrome.