The incidence is estimated to range from 0.1–1.2 per 10,000 live births, though the true incidence is unknown. As of 2005, the highest prevalence was found in Canada and estimated at 1 in 8,500 live births.

The recurrence of DOOR in siblings and the finding of DOOR syndrome in a few families with consanguinity suggest that the condition is an autosomal recessive genetic condition. Mutations in TBC1D24 have been identified in 9 families.

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.

In itself, NSML is not a life-threatening diagnosis, most people diagnosed with the condition live normal lives. Obstructive cardiomyopathy and other pathologic findings involving the cardiovascular system may be a cause of death in those whose cardiac deformities are profound.

There is no known cure for this syndrome. Patients usually need ophthalmic surgery and may also need dental surgery

Genetic counseling and screening of the mother's relatives is recommended.

This syndrome is due to mutations in the Nance Horan gene (NHS) which is located on the short arm of the X chromosome (Xp22.13).

SCS is the most common craniosynostosis syndrome and affects 1 in every 25,000 to 50,000 individuals. It occurs in all racial and ethnic groups, and affects males and females equally. If a parent carries a copy of the SCS gene mutation, then there is a 50% chance their child will also carry a copy of the gene mutation, in which case, the child may or may not show signs of SCS. There is also a 50% chance their child will have two working copies of the gene, and would therefore, not have SCS. If both parents carry a single copy of the SCS gene mutation, then there is a 25% chance their child will have two gene mutation copies (so child would develop severe SCS), a 25% chance their child would have two normal copies of the gene (so would be completely normal), and a 50% chance their child would carry one gene mutation copy and 1 normal copy (so child may or may not display SCS). In rare situations, two normal parents can have a child with SCS due to a "de novo" mutation. The exact cause of the "de novo" mutation is unknown, but it doesn't seem to be related to anything that the parents did or didn't do during the pregnancy. SCS due to a "de novo" mutation is so rare that the proportion of past cases is unknown.

This disorder is caused by an abnormality of the TBCE gene, the locus for which is on Chromosome 1q42.3. The locus is a 230 kb region of gene with identified deletions and mutations in affected individuals. There are rare cases of the disorder not being due to a TBCE gene abnormality.

CHARGE syndrome was formerly referred to as CHARGE association, which indicates a non-random pattern of congenital anomalies that occurs together more frequently than one would expect on the basis of chance. Very few people with CHARGE will have 100% of its known features. In 2004, mutations on the CHD7 gene (located on Chromosome 8) were found in 10 of 17 patients in the Netherlands, making CHARGE an official syndrome. A US study of 110 individuals with CHARGE syndrome showed that 60% of those tested had a mutation of the CHD7 gene.

In 2010, a review of 379 clinically diagnosed cases of CHARGE syndrome, in which CHD7 mutation testing was undertaken found that 67% of cases were due to a CHD7 mutation. CHD7 is a member of the chromodomain helicase DNA-binding (CHD) protein family that plays a role in transcription regulation by chromatin remodeling.

Kaufman oculocerebrofacial syndrome is an autosomal recessive congenital disorder characterized by mental retardation, brachycephaly, upslanting palpebral fissures, eye abnormalities, and highly arched palate. It was characterized in 1971; eight cases had been identified as of 1995.

There is no specific treatment for micro syndrome, but there are ways to help the disorders, and illnesses that come with it. Many individuals with Micro Syndrome need permanent assistance from their disorders and inabilities to move and support themselves. Seizures are not uncommon and patients should get therapy to help control them, and many patients also require wheelchairs to move, so an assistant would be needed at all times.

Those with micro syndrome are born appearing normal. At the age of one, mental and physical delays become apparent, along with some limb spasms. By the age of eight micro syndrome has already set in, and the patient will have joint contractures, Ocular Atrophy will become noticeable, the patient will most likely lose ability to walk, speak, and sometimes move at all.

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.

The rare cases that have been examined are often within families, or the people that have cases of micro syndrome have a mutation in their genes.

It can be associated with "RAB3GAP".

Research on the risk for developing schizophrenia in Ashkenazi Jews and other populations showed that 3q29 microdeletion syndrome leads to a significant higher rate of schizophrenia.

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).

The cause of this condition is apparently due to mutation in the UBE3B gene and is inherited via autosomal recessive manner. This gene is located at molecular location- base pairs 109,477,410 to 109,543,628 and position 24.11 on chromosome 12.

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.

Smith–Fineman–Myers syndrome (SFMS1), congenital disorder that causes birth defects. This syndrome was named after 3 men, Richard D. Smith, Robert M. Fineman and Gart G. Myers who discovered it around 1980.

Cohen syndrome (also known as Pepper syndrome or Cervenka syndrome, named after Michael Cohen, William Pepper and Jaroslav Cervenka, who researched the illness) is a genetic disorder.

In the two predominant mutations of NSML (Y279C and T468M) the mutations cause a loss of catalytic activity of the SHP2 protein (the gene product of the "PTPN11" gene), which is a previously unrecognized behavior for this class of mutations. This interferes with growth factor and related signalling. While further research confirms this mechanism, additional research is needed to determine how this relates to all of the observed effects of NSML.

In at least some case, the gene lesion involves a mutation in the "CSB" gene.

It can be associated with "ERCC6".

Hennekam syndrome also known as intestinal lymphagiectasia–lymphedema–mental retardation syndrome, is an autosomal recessive disorder consisting of intestinal lymphangiectasia, facial anomalies, peripheral lymphedema, and mild to moderate levels of growth and intellectual disability.

It is also known as "lymphedema-lymphangiectasia-mental retardation syndrome".

In a subset of patients it is associated with CCBE1 according research published by its namesake, Raoul Hennekam. Other causal mutations were found in the FAT4 gene. Previously, mutations in the FAT4 gene had been only associated with van Maldergem syndrome. The molecular mechanism of the lymphedema phenotype in CCBE1-associated cases was identified as a diminished ability of the mutated CCBE1 to accelerate and focus the activation of the primary lymphangiogenic growth factor VEGF-C.

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

It was characterized in 1989.

DeSanctis–Cacchione syndrome is an extremely rare disorder characterized by the skin and eye symptoms of xeroderma pigmentosum (XP) occurring in association with microcephaly, progressive mental retardation, retarded growth and sexual development, deafness, choreoathetosis, ataxia and quadriparesis.

Presenting at birth, features of the disorder include moderately severe IUGR, microcephaly, craniosynostosis, moderately severe post uterine growth retardation, deafness, deep set eyes, cryptorchidism, truncal obesity and acanthosis nigricans, small teeth, prognathism, dislocated radial heads without generalized skeletal dysplasia, however, tall vertebrae, moderate mental retardation, hypothyroidism, insulin resistance, hypoparathyroidism.