Sack–Barabas syndrome is rare and has an estimated prevalence of 1 in 100,000 to 200,000.

The initial clinical manifestation of vascular problems in patients with SBS is early, about 25% have their first symptoms at age 20 and more than 80% of patients have had at least one complication by the age of 40.

The median survival for one study of SBS patients was only 48 years.

Not to be confused with Rosenthal syndrome a.k.a hemophilia C which is caused by clotting factor XI deficiency. Only genetic causation is established as it is associated with twins and family members.

Melkersson–Rosenthal syndrome may recur intermittently after its first appearance. It can become a chronic disorder. Follow-up care should exclude the development of Crohn's disease or sarcoidosis.

Nablus mask-like facial syndrome is a microdeletion syndrome triggered by a deletion at chromosome 8 q22.1 that causes a mask-like facial appearance in those affected.

It is characterized by a narrowing of the eyes, tight, glistening facial skin, and a flat, broad nose. Other features of the syndrome include malformed ears, unusual hair patterns on the scalp, bent fingers and toes and joint deformities in the hands and feet, unusual teeth, mild developmental delay, cryptorchidism, and a generally happy disposition. It is a rare genetic disorder by inheritance found in Palestinian people named after Nablus city in the West Bank. It is part of many new genetic disorders of newborns that is increasing exponentially in Arabs in recent years as reported by Centre for Arab Genomic Studies in Dubai.

The cause is unknown, but it may be partly a genetic trait. Aging and environmental factors may also contribute to the appearance.

Kleefstra syndrome affects males and females equally and approximately, 75% of all documented cases are caused by Eu-HMTase1 disruptions while only 25% are caused by 9q34.3 deletions. There are no statistics on the effect the disease has on life expectancy due to the lack of information available.

Fissured tongue is seen in Melkersson-Rosenthal syndrome (along with facial nerve paralysis and granulomatous cheilitis). It is also seen in most patients with Down syndrome, in association with geographic tongue, in patients with oral manifestations of psoriasis, and in healthy individuals. Fissured tongue is also sometimes a feature of Cowden's syndrome.

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.

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.

Keppen–Lubinsky syndrome (KPLBS) is an extremely rare congenital disorder.The minimal clinical criteria for the Keppen–Lubinsky syndrome are as follows: normal growth parameters at birth, postnatal growth failure, peculiar face with an aged appearance (large prominent eyes, a narrow nasal bridge, a tented upper lip, a high palate, an open mouth), skin tightly adherent to facial bones, generalized lipodystrophy, microcephaly, and development delay. Keppen-Lubinsky syndrome is caused by mutation in the inwardly rectifying K+ channels encoded by KCNJ6 gene.

Miller-Dieker occurs in less than one in 100000 people and can occur in all races.

The key for managing Sack–Barabas syndrome is for the patient to be aware of their disease. Close follow up and planning of interventions can significantly prolong and maintain the quality of life of a patient with this disease.

Pregnant affected women must take special care due to the increased risk of premature death due to rupture of arteries, bowel or uterine rupture with a reported mortality rate of 50%.

Genetic counselling is recommended for prospective parents with a family history of Ehlers–Danlos syndrome. Affected parents should be aware of the type of Ehlers-Danlos syndrome they have and its mode of inheritance.

Costello and Noonan syndrome are similar to CFC and their phenotypic overlap may be due to the biochemical relationship of the genes mutated in each syndrome to each other. Genes that are mutated in all three of these syndromes encode proteins that function in the MAP kinase pathway.

- Mutations that cause CFC are found in the KRAS, BRAF, MEK1 and MEK2 genes.

- Costello syndrome is caused by mutations in HRAS.

- Mutations that cause Noonan syndrome have been found in PTPN11 and SOS1.

The relative severity of CFC when compared to Noonan syndrome may reflect the position in the biochemical pathway each gene occupies.

- Shp2, the protein product of the PTPN11, appears to regulate the MAP kinase pathway at or above the level of SOS1.

- SOS1 in turn regulates the activities of RAS, RAF, MEK, ERK and p90RSK.

- SOS1 has been demonstrated to be a target of negative feedback by ERK and p90RSK.

Thus, any activating mutation downstream of SOS1 may be subject to less regulation that may mitigate the consequence of such mutations giving rise to the phenotypic differences seen between these syndromes.

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.

Nevo Syndrome is considered to be a rare disorder. Since its first appearance in 1974, only a handful of cases have been reported. Studies have shown showing similarities between Nevo Syndrome with Ehlers-Danlos syndrome as well as Sotos syndrome. There is an astounding overlap of phenotypic manifestations between Nevo Syndrome and the more frequent Sotos syndrome, which are both caused by the NSD1 deletion. Sotos syndrome is an autosomal dominant condition associated with learning disabilities, a distinctive facial appearance, and overgrowth. Studies have shown an overwhelming occurrence (half of those involved in the study) of Nevo syndrome in those individuals of Middle-Eastern descent.

A unibrow is part of normal human variation, but can also stem from developmental disorders. A unibrow is a recognized feature of Cornelia De Lange syndrome, a genetic disorder whose main features include moderate to severe learning difficulties, limb abnormalities such as oligodactyly (fewer than normal fingers or toes) and phocomelia (malformed limbs), and facial abnormalities including a long philtrum (the slight depression/line between the nose and mouth).

Other medical conditions associated with a unibrow include:

- Waardenburg Syndrome;

- Patau Syndrome;

- Smith-Lemli-Opitz Syndrome;

- Sanfilippo Syndrome;

- 3p Deletion Syndrome;

- Chromosome Deletion Dillan 4p Syndrome (Wolf–Hirschhorn Syndrome);

- Gorlin Syndrome (Basal Cell Nevus Syndrome);

- Frontometaphyseal Dysplasia;

- ATRX Syndrome;

- Chromosome 9q34 Microdeletion Syndrome or Kleefstra syndrome.

Due to its recent discovery, there are currently no existing treatments for Kleefstra syndrome.

Pitt–Hopkins syndrome is a rare genetic disorder characterized by developmental delay, a wide mouth, distinctive facial features, and intermittent hyperventilation followed by apnea. It is associated with an abnormality within chromosome 18: specifically, it is caused by an insufficient expression of the TCF4 gene.

Overall, the estimated prevalence of Stickler syndrome is about 1 in 10,000 people. Stickler syndrome affects 1 in 7,500 to 9,000 newborns.

Ramos-Arroyo syndrome is marked by corneal anesthesia, absence of the peripapillary choriocapillaris and retinal pigment epithelium, bilateral sensorineural hearing loss, unusual facial appearance, persistent ductus arteriosus, Hirschsprung disease, and moderate intellectual disability. It appears to be a distinct autosomal dominant syndrome with variable expressivity.

As of 2008 this syndrome has only been reported in five individuals within three generations of the same family; two young children, their mother, their uncle and their maternal grandmother. This most recent generation to be diagnosed with Ramos-Arroyo syndrome supports the hypothesis that this disease is a distinct autosomal

dominant disorder. If this syndrome could be identified in other families it may help to discriminate the gene responsible.

The condition was first described in 1978 by Pitt and Hopkins in two unrelated patients.

The genetic cause of this disorder was described in 2007. This disorder is due to a haploinsufficiency of the transcription factor 4 (TCF4) gene which is located on the long arm of chromosome 18 (18q21.2) The mutational spectrum appears to be 40% point mutations, 30% small deletions/insertions and 30% deletions. All appear to be "de novo" mutations and to date no risk factors have been identified.

A Pitt–Hopkins like phenotype has been assigned to autosomal recessive mutations of the contactin associated protein like 2 (CNTNAP2) gene on the long arm of chromosome 7 (7q33-q36) and the neurexin 1 alpha (NRXN1) gene on the short arm of chromosome 2 (2p16.3).

Many professionals that are likely to be involved in the treatment of those with Stickler's syndrome, include anesthesiologists, oral and maxillofacial surgeons; craniofacial surgeons; ear, nose, and throat specialists, ophthalmologists, optometrists, audiologists, speech pathologists, physical therapists and rheumatologists.

The cause of this condition is unknown but evidence of familial inheritance and sporadic genetic mutation has been linked to cases of FHS. Two possibly familial cases have been reported—one in a mother and son, and the other in a mother and daughter. This suggests an autosomal dominant inheritance but additional cases need to be investigated to establish this. Another report has suggested that the inheritance may be autosomal recessive. In all of these cases, however, the mothers and children were not similarly affected, suggesting a variable clinical expression of the syndrome.

In a study published by the "American Journal of Human Genetics" in 2012, exome sequencing was used to investigate a group of unrelated individuals with classic features of FHS and identified heterozygous mutations in SRCAP as causative of this disorder. Each reported mutation was truncating (nonsense or frameshift) and occurred between codons 2,407 and 2,517 in exon 34, resulting in the loss of three C-terminal AT-hook motifs. SRCAP encodes a SNF2-related chromatin-remodeling ATPase that is a coactivator for CREB-binding protein (or CBP), which is the major cause of Rubinstein–Taybi syndrome. This disrupted interaction between the proteins most likely explains the clinical overlap between FHS and RTS.

- SRCAP has been shown to transduce signals of nuclear (steroid) hormone receptors and Notch pathways, showing that it plays diverse roles in gene expression.

- SRCAP contains several functional domains (SNF2 like ATPase, an N-terminal HSA domain, and three C-terminal AT-hook DNA-binding motifs).

- The CBP interaction domain of SRCAP is located centrally.

Thus, the mechanism of disease in FHS is suspected to be dominant-negative (or antimorphic) due to the mutation in the final exon that results in the loss of the major transactivation function of SRCAP (or loss of one or more critical domains). All of the patients that carried the mutation also had obvious physical symptoms (i.e., prominent nose, delayed bone age, and short stature). Those who tested negative for the mutation often had dysmorphic facial features distinct from classical FHS, as well as a formal diagnosis of autism.

Nevo Syndrome is an autosomal recessive disorder. Most times in which a child is afflicted with Nevo Syndrome, both their parents are of average height and weight. It is only until after birth when the characteristic physical traits associated with disease are manifested, and the disorder is actually diagnosed. One study showed that despite the increased growth rates, the patient was completely healthy up until age 6, when he was admitted into the hospital. Nevo syndrome is usually associated with early childhood fatality. Children with Nevo Syndrome have a high occurrence of death due to cardiac arrest because their developing hearts cannot keep up with their overgrown body.

A review from 2000 stated that life expectancy was reduced because of a tendency to develop cancer relatively early as well as deaths due to infections related to immunodeficiency.