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.

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.

Three main support groups of this syndrome are the ASGA in Australia, The Association for Children with Genetic Disorders in Poland, and the Association of People of Genetic Disorders in Greece.

MURCS association (a variant of Mayer-Rokitansky-Küster-Hauser syndrome) is a very rare developmental disorder that primarily affects the reproductive and urinary systems involving MUllerian agenesis, Renal agenesis, Cervicothoracic Somite abnormalities. It affects only females.

The genetic disorder Yemenite deaf-blind hypopigmentation syndrome, also known as Warburg-Thomsen syndrome, is a condition caused by a mutation on the SRY-related HMG-box gene 10 (not SOX10).

It was characterized in 1990, after being seen in two siblings from Yemen who presented with a "hitherto undescribed association of microcornea, colobomata of the iris and choroidea, nystagmus, severe early hearing loss, and patchy hypo- and hyperpigmentation." Some sources affirm "SOX10" involvement.

Patients with abnormal cardiac and kidney function may be more at risk for hemolytic uremic syndrome

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.

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.

BFS has been reported in other African cultures, and also in Brazil, Argentina, and Ethiopian Jews. Historic higher reported prevalence among males may be due to more males being present in higher education in African countries. Studies since the 1990s have not verified gender differences. Other studies found a possible association with low socioeconomic status, an association with average or higher intelligence, and a high association with neuroticism. Individuals with BFS have been found to have problems with isolation, poor study habits, and the use of psychostimulants as well as physical changes including in muscle tension and heart rate.

Lelis syndrome it is a genetic disorder, a rare condition with dermatological and dental findings characterized by the association of ectodermal dysplasia (hypotrichosis and hypohidrosis) with acanthosis nigricans. Other clinical features may include palmoplantar hyperkeratosis, nail dystrophy, intellectual deficit, disturbances of skin pigmentation (perioral and periorbital hyperpigmentation, vitiligo, and perinevic leukoderma) and hypodontia. Transmission is autosomal recessive.

The incidence of VACTERL association is estimated to be approximately 1 in 10,000 to 1 in 40,000 live-born infants. It is seen more frequently in infants born to diabetic mothers. While most cases are sporadic, there are clearly families who present with multiple involved members.

The cytogenetic location is 7q36 and genomic coordinates are GRCh37:147,900,000 - 159,138,663 (NCBI). Mapping of this syndrome was done by Dundar and coworkers in 2001. They showed that this phenotype was linked to a 6.4-cM region of 7q36 flanked by the EN2 gene and the marker D7S2423. Dundar and coworkers characterized and mapped acropectoral syndrome and also showed it was unrelated to acropectorovertebral syndrome. The mapping showed that the acropectoral locus was in a region where preaxial polydactyly and triphalangeal thumb-polysyndactyly had previously been mapped. This study was important because it expanded the range of phenotypes that are connected to this locus. Previously, preaxial polydactyly and sternal defects have been linked to expression of the gene Sonic hedgehog Shh in limbbud and lateral plate mesoderm during development in mice. Dundar and coworkers found that the LMBR1 gene links to pre axial polydactyly. This gene encodes for a new transmembrane receptor and it is proposed that this receptor is an upstream regulator of SHH.

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

It can be associated with "ERCC6".

Renal-hepatic-pancreatic dysplasia is an autosomal recessive congenital disorder characterized by pancreatic fibrosis, renal dysplasia and hepatic dysgenesis. It is usually fatal soon after birth.

An association with NPHP3 has been described.

It was characterized in 1959.

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.

These lesions usually present in neonates, although they may not come to clinical attention until adulthood (for cosmetic reasons). There is no gender predilection. They are present in approximately 3-6 per 1000 live births.

A syndrome is a set of medical signs and symptoms occurring together, constitutes a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". In some instances, a syndrome is so closely linked with a pathogenesis or cause that the words "syndrome", "disease", and "disorder" end up being used interchangeably for them. This is especially true of inherited syndromes. For example, Down syndrome, Wolf–Hirschhorn syndrome, and Andersen syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite the "syndrome" nomenclature. In other instances, a syndrome is not specific to only one disease. For example, toxic shock syndrome can be caused by various toxins; premotor syndrome can be caused by various brain lesions; and premenstrual syndrome is not a disease but simply a set of symptoms.

If an underlying genetic cause is suspected but not known, a condition may be referred to as a genetic association (often just "association" in context). By definition, an association indicates that the collection of signs and symptoms occurs in combination more frequently than would be likely by chance alone.

Syndromes are often named after the physician or group of physicians that discovered them or initially described the full clinical picture. Such eponymous syndrome names are examples of medical eponyms. Recently, there has been a shift towards naming conditions descriptively (by symptoms or underlying cause) rather than eponymously, but the eponymous syndrome names often persist in common usage.

WNT4 (found on the short arm (p) of chromosome 1) has been clearly implicated in the atypical version of this disorder. A genetic mutation causes a leucine to proline residue substitution at amino acid position 12. This occurrence reduces the intranuclear levels of β catenin. In addition, it removes the inhibition of steroidogenic enzymes like 3β-hydroxysteriod dehydrogenase and 17α-hydroxylase. Patients therefore have androgen excess. Furthermore, without WNT4, the Müllerian duct is either deformed or absent. Female reproductive organs, such as the cervix, fallopian tubes, ovaries, and much of the vagina, are hence affected.

An association with a deletion mutation in the long arm (q) of chromosome 17 (17q12) has been reported. The gene LHX1 is located in this region and may be the cause of a number of these cases.

Dennie–Marfan syndrome is a syndrome in which there is association of spastic paraplegia of the lower limbs and mental retardation in children with congenital syphilis. Both sexes are affected, and the onset of the disease can be acute or insidious, with slow progression from weakness to quadriplegia. Epilepsy, cataract, and nystagmus may be also be found.

The syndrome was described by Charles Clayton Dennie in 1929, and Antoine Marfan in 1936.

Anumonye reported treatment success with lorazepam; others found benefit with antidepressants and relaxation exercises.

Even in syndromes with no known etiology, the presence of the associated symptoms with a statistically improbable correlation, normally leads the researchers to hypothesize that there exists an unknown underlying cause for all the described symptoms.

Congenital fiber type disproportion (CFTD) is an inherited form of myopathy with small type 1 muscle fibers that may occur in a number of neurological disorders. It has a relatively good outcome and follows a stable course. While the exact genetics is unclear there is an association with TPM3, ACTA1 and SEPN1 gene mutations. It is a rare condition.

The prevalence remains sparsely investigated. To date, two population-based nationwide studies have been conducted both estimating a prevalence about 1 in 5000 live female births. According to some reports, Queen Amalia of Greece may have had the syndrome, but a 2011 review of the historical evidence concludes that it is not possible to determine the inability of her and her husband to have a child. Her inability to provide an heir contributed to the overthrow of her husband, King Otto.

The cataract-microcornea syndrome is the association of congenital cataract and microcornea.

Keratosis follicularis spinulosa decalvans (also known as "Siemens-1 syndrome") is a rare X-linked disorder described by Siemens in 1926, a disease that begins in infancy with keratosis pilaris localized on the face, then evolves to more diffuse involvement.

An association with SAT1 has been suggested.