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.

Acrocephalosyndactylia (or acrocephalosyndactyly) is the common presentation of craniosynostosis and syndactyly.

While not always pathological, it can present as a birth defect in multiple syndromes including:

- Catel–Manzke syndrome

- Bloom syndrome

- Coffin–Lowry syndrome

- congenital rubella

- Cri du chat syndrome

- DiGeorge's syndrome

- Ehlers-Danlos syndrome

- fetal alcohol syndrome

- Hallermann-Streiff syndrome

- Hemifacial microsomia (as part of Goldenhar syndrome)

- Juvenile idiopathic arthritis

- Marfan syndrome

- Noonan syndrome

- Pierre Robin syndrome

- Prader–Willi syndrome

- Progeria

- Russell-Silver syndrome

- Seckel syndrome

- Smith-Lemli-Opitz syndrome

- Treacher Collins syndrome

- Trisomy 13 (Patau syndrome)

- Trisomy 18 (Edwards syndrome)

- Wolf–Hirschhorn syndrome

- X0 syndrome (Turner syndrome)

It has several different types:

- type 1 - Apert syndrome

- type 2 - Crouzon syndrome

- type 3 - Saethre-Chotzen syndrome

- type 5 - Pfeiffer syndrome

A related term, "acrocephalopolysyndactyly" (ACPS), refers to the inclusion of polydactyly to the presentation. It also has multiple types:

- type 1 - Noack syndrome; now classified with Pfeiffer syndrome

- type 2 - Carpenter syndrome

- type 3 - Sakati-Nyhan-Tisdale syndrome

- type 4 - Goodman syndrome; now classified with Carpenter syndrome

- type 5 - Pfeiffer syndrome

It has been suggested that the distinction between "acrocephalosyndactyly" versus "acrocephalopolysyndactyly" should be abandoned.

It can be detected by the naked eye as well as dental or skull X-Ray testing.

Schimmelpenning syndrome appears to be sporadic rather than inherited, in almost all cases. It is thought to result from genetic mosaicism, possibly an autosomal dominant mutation arising after conception and present only in a subpopulation of cells. The earlier in embryological development such a mutation occurs, the more extensive the nevi are likely to be and the greater the likelihood of other organ system involvement.

Orofaciodigital syndrome 1 (OFD1), also called Papillon-League and Psaume syndrome, is an X-linked congenital disorder characterized by malformations of the face, oral cavity, and digits with polycystic kidney disease and variable involvement of the central nervous system.

Recent findings in genetic research have suggested that a large number of genetic disorders, both genetic syndromes and genetic diseases, that were not previously identified in the medical literature as related, may be, in fact, highly related in the genotypical root cause of these widely varying, phenotypically-observed disorders. Orofaciodigital syndrome has been found to be a ciliopathy. Other known ciliopathies include primary ciliary dyskinesia, Bardet-Biedl syndrome, polycystic kidney disease and polycystic liver disease, nephronophthisis, Alstrom syndrome, Meckel-Gruber syndrome and some forms of retinal degeneration.

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 likely that this syndrome is inherited in an autosomal dominant fashion, however there may be a recessive form with hypotonia and developmental delay.

Males are twice as likely as females to have this characteristic, and it tends to run in families. In its non-symptomatic form, it is more common among Asians and Native Americans than among other populations, and in some families there is a tendency to inherit the condition unilaterally, that is, on one hand only.

The presence of a single transverse palmar crease can be, but is not always, a symptom associated with abnormal medical conditions, such as fetal alcohol syndrome, or with genetic chromosomal abnormalities, including Down Syndrome (chromosome 21), cri du chat syndrome (chromosome 5), Klinefelter syndrome, Wolf-Hirschhorn Syndrome, Noonan syndrome (chromosome 12), Patau syndrome (chromosome 13), IDIC 15/Dup15q (chromosome 15), Edward's syndrome (chromosome 18), and Aarskog-Scott syndrome (X-linked recessive), or autosomal recessive disorder, such as Leaukocyte adhesion deficiency-2 (LAD2). A unilateral single palmar crease was also reported in a case of chromosome 9 mutation causing Nevoid basal cell carcinoma syndrome and Robinow syndrome. It is also sometimes found on the hand of the affected side of patients with Poland Syndrome, and craniosynostosis.

Muenke syndrome is caused by a specific gene mutation in the FGFR3 gene. The mutation arises randomly; there is no full understanding for what causes this mutation. This mutation causes the FGFR3 protein to be overly active; it interferes with normal bone growth, and allows skull bones to fuse prematurely. There is no connection between anything mother did (or did not do) to activate the syndrome. If neither of the parents have Muenke syndrome, chances of having another child with the syndrome are minimal.

This condition is inherited in an autosomal dominant pattern. This means if a parent has Muenke syndrome, every newborn has a 50% chance of inheriting the syndrome.

At this time, there are no other phenotypes (observable expressions of a gene) that have been discovered for mutations in the ESCO2 gene.

Muenke syndrome is inherited in an autosomal dominant pattern. In some cases, an affected person inherits the mutation from one affected parent. If a patient is shown to have Muenke, they have a 50/50 chance of passing it on to their children. Not all cases of Muenke however is obvious. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

A single mutation in the FGFR3 gene cause this syndrome. The FGFR3 gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. This mutation causes the FGFR3 protein to be overly active, which interferes with normal bone growth and allows the bones of the skull to fuse before they should.

As stated by researchers at the University of Washington, Muenke syndrome is inherited in an autosomal dominant manner with incomplete penetrance and variable expressivity.” Prenatal diagnosis for pregnancies at increased risk is possible if the defining mutation has been identified in the family (Agochukwu et.al. 2006). According to the article "Craniosynostosis: Molecular Genetics," penetrance is higher in females (87%) than in males (76%). Muenke syndrome is estimated to account for 25%-30% of all genetic causes of craniosynostosis according to the Journal of Anatomy.

The RASopathies are developmental syndromes caused by germline mutations (or in rare cases by somatic mosaicism) in genes that alter the Ras subfamily and mitogen-activated protein kinases that control signal transduction, including:

- Capillary malformation-AV malformation syndrome

- Autoimmune lymphoproliferative syndrome

- Cardiofaciocutaneous syndrome

- Hereditary gingival fibromatosis type 1

- Neurofibromatosis type 1

- Noonan syndrome

- Costello syndrome, Noonan-like

- Legius syndrome, Noonan-like

- Noonan syndrome with multiple lentigines, formerly called LEOPARD syndrome, Noonan-like

The incidence of Fraser syndrome is 0.043 per 10,000 live born infants and 1.1 in 10,000 stillbirths, making it a rare syndrome.

Omphalocele has been described in two patients with Apert syndrome by Herman T.E. et al. (USA, 2010) and by Ercoli G. et al. (Argentina, 2014). An omphalocele is a birth defect in which an intestine or other abdominal organs are outside of the body of an infant because of a hole in the bellybutton area. However, the association between omphalocele and Apert syndrome is not confirmed yet, so additional studies are necessary.

The original report was of a family in Cardiff, United Kingdom. There are subsequent reports of patients from the USA, France, Australia, UAE, India and from Cuba.

The specific cause of camptodactyly remains unknown, but there are a few deficiencies that lead to the condition. A deficient lumbrical muscle controlling the flexion of the fingers, and abnormalities of the flexor and extensor tendons.

A number of congenital syndromes may also cause camptodactyly:

- Jacobsen syndrome

- Beals Syndrome

- Blau syndrome

- Freeman-Sheldon syndrome

- Cerebrohepatorenal syndrome

- Weaver syndrome

- Christian syndrome 1

- Gordon Syndrome

- Jacobs arthropathy-camptodactyly syndrome

- Lenz microphthalmia syndrome

- Marshall-Smith-Weaver syndrome

- Oculo-dento-digital syndrome

- Tel Hashomer camptodactyly syndrome

- Toriello-Carey syndrome

- Stuve-Wiedemann syndrome

- Loeys-Dietz syndrome

- Fryns syndrome

- Marfan's syndrome

- Carnio-carpo-tarsal dysthropy

A high-arched palate (also termed high-vaulted palate) is where the palate is unusually high and narrow. It is usually a developmental feature that may occur in isolation or in association with a number of conditions. It may also be an acquired condition caused by chronic thumb-sucking. High-arched palate may cause narrowed airway and sleep disordered breathing.

Example conditions which may be associated with high-arched palate include:

- Crouzon syndrome

- Down syndrome

- Apert syndrome

- Treacher Collins syndrome

- Marfan syndrome

- Incontinentia pigmenti

Perlman syndrome is a rare disease with an estimated incidence of less than 1 in 1,000,000. As of 2008, less than 30 patients had ever been reported in the world literature.

Low-set ears are ears with depressed positioning of the pinna two or more standard deviations below the population average.

It can be associated with conditions such as:

- Down's syndrome

- Turner Syndrome

- Noonan syndrome

- Patau syndrome

- DiGeorge syndrome

- Cri du chat syndrome

- Edwards syndrome

- Fragile X syndrome

It is usually bilateral, but can be unilateral in Goldenhar syndrome.

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).

Heart-hand syndrome type 2 is also known as Berk–Tabatznik syndrome. Berk–Tabatznik syndrome is a condition with an unknown cause that shows symptoms of short stature, congenital optic atrophy and brachytelephalangy. This condition is extremely rare with only two cases being found.

Heart-hand syndrome type 3 is very rare and has been described only in three members of a Spanish family. It is also known as Heart-hand syndrome, Spanish type.