More than 30 different signs and symptoms are variably associated with Marfan syndrome. The most prominent of these affect the skeletal, cardiovascular, and ocular systems, but all fibrous connective tissue throughout the body can be affected.

Most of the readily visible signs are associated with the skeletal system. Many individuals with Marfan syndrome grow to above-average height, and some have disproportionately long, slender limbs with thin, weak wrists and long fingers and toes. Besides affecting height and limb proportions, people with Marfan syndrome may have abnormal lateral curvature of the spine (scoliosis), thoracic lordosis, abnormal indentation (pectus excavatum) or protrusion (pectus carinatum) of the sternum, abnormal joint flexibility, a high-arched palate with crowded teeth and an overbite, flat feet, hammer toes, stooped shoulders, and unexplained stretch marks on the skin. It can also cause pain in the joints, bones and muscles. Some people with Marfan have speech disorders resulting from symptomatic high palates and small jaws. Early osteoarthritis may occur. Other signs include limited range of motion in the hips due to the femoral head protruding into abnormally deep hip sockets.

There is considerable variability in the phenotype of Loeys–Dietz syndrome, from mild features to severe systemic abnormalities. The primary manifestations of Loeys–Dietz syndrome are arterial tortuosity (winding course of blood vessels), widely spaced eyes (hypertelorism), wide or split uvula, and aneurysms at the aortic root. Other features may include cleft palate and a blue/gray appearance of the white of the eyes. Cardiac defects and club foot may be noted at birth.

There is overlap in the manifestations of Loeys–Dietz and Marfan syndromes, including increased risk of ascending aortic aneurysm and aortic dissection, abnormally long limbs and fingers, and dural ectasia (a gradual stretching and weakening of the dura mater that can cause abdominal and leg pain). Findings of hypertelorism (widely spaced eyes), bifrid or split uvula, and skin findings such as easy bruising or abnormal scars may distinguish Loys-Dietz from Marfan syndrome.

Findings of Loys-Dietz syndrome may include:

- Skeletal/spinal malformations: craniosynositosis, Scoliosis, spinal instability and spondylolisthesis, Kyphosis

- Sternal abnormalities: pectus excavatum, pectus carinatum

- Contractures of fingers and toes (camptodactyly)

- Long fingers and lax joints

- Weakened or missing eye muscles (strabismus)

- Club foot

- Premature fusion of the skull bones (craniosynostosis)

- Joint hypermobility

- Congenital heart problems including patent ductus arteriosus (connection between the aorta and the lung circulation) and atrial septal defect (connection between heart chambers)

- Translucency of the skin with velvety texture

- Abnormal junction of the brain and medulla (Arnold-Chiari malformation)

- Bicuspid aortic valves

- Criss-crossed pulmonary arteries

Loeys–Dietz syndrome (LDS) is an autosomal dominant genetic connective tissue disorder. It has features similar to Marfan syndrome and Ehlers–Danlos syndrome. The disorder is marked by aneurysms in the aorta, often in children, and the aorta may also undergo sudden dissection in the weakened layers of the wall of aorta. Aneurysms and dissections also can occur in arteries other than the aorta. Because aneurysms in children tend to rupture early, children are at greater risk for dying if the syndrome is not identified. Surgery to repair aortic aneurysms is essential for treatment.

There are four types of the syndrome, labelled types I through IV, which are distinguished by their genetic cause. Type 1, Type 2, Type 3, and Type 4 are caused by mutations in "TGFBR1", "TGFBR2", "SMAD3", and "TGFB2" respectively. These four genes encoding transforming growth factors play a role in cell signaling that promotes growth and development of the body's tissues. Mutations of these genes cause production of proteins without function. Although the disorder has an autosomal pattern of inheritance, this disorder results from a new gene mutation in 75% of cases and occurs in people with no history of the disorder in their family.

Loeys-Dietz syndrome was identified and characterized by pediatric geneticists Bart Loeys and Harry Dietz at Johns Hopkins University in 2005.

Of the following common symptoms of Turner syndrome, an individual may have any combination of symptoms and is unlikely to have all symptoms.

- Short stature

- Lymphedema (swelling) of the hands and feet of a newborn

- Broad chest (shield chest) and widely spaced nipples

- Low posterior hairline

- Low-set ears

- Reproductive sterility

- Rudimentary ovaries gonadal streak (underdeveloped gonadal structures that later become fibrotic)

- Amenorrhoea, the absence of a menstrual period

- Increased weight, obesity

- Shortened metacarpal IV

- Small fingernails

- Characteristic facial features

- Webbed neck from cystic hygroma in infancy

- Aortic valve stenosis

- Coarctation of the aorta

- Bicuspid aortic valve (most common cardiac problem)

- Horseshoe kidney

- Visual impairments – sclera, cornea, glaucoma, etc.

- Ear infections and hearing loss

- High waist-to-hip ratio (the hips are not much bigger than the waist)

- Attention deficit hyperactivity disorder (problems with concentration, memory, attention with hyperactivity seen mostly in childhood and adolescence)

- Nonverbal learning disability (problems with maths, social skills, and spatial relations)

Other features may include a small lower jaw (micrognathia), cubitus valgus, soft upturned nails, palmar crease, and drooping eyelids. Less common are pigmented moles, hearing loss, and a high-arch palate (narrow maxilla). Turner syndrome manifests itself differently in each female affected by the condition; therefore, no two individuals share the same features.

While most of the physical findings are harmless, significant medical problems can be associated with the syndrome. Most of these significant conditions are treatable with surgery and medication.

Cardiac defects are similar to those associated with Marfan's syndrome, a disorder of the connective tissue.

- Elongation of aorta

- Bicuspid aortic valve

- Subaortic stenosis

- Mitral valve prolapse with mitral regurgitation

- Atrial septal defect

- Patent ductus arteriosus

- Tricuspid valve prolapse

- Aortic dissection and aneurysm

- Aneurysm of ductus arteriosus

The most commonly observed are congenital obstructive lesions of the left side of the heart, leading to reduced flow on this side of the heart. This includes bicuspid aortic valve and coarctation (narrowing) of the aorta. More than 50% of the cardiovascular malformations of individuals with Turner syndrome in one study were bicuspid aortic valves or coarctation of the aorta (usually preductal), alone or in combination.

Other congenital cardiovascular malformations, such as partial anomalous venous drainage and aortic valve stenosis or aortic regurgitation, are also more common in Turner syndrome than in the general population. Hypoplastic left heart syndrome represents the most severe reduction in left-sided structures.

These symptoms were found in rare cases of Larsen syndrome.

- Cataracts

- Cleft palate

- Extra bones of wrist

- Malocclusion

- Microdontia and hypodontia

- Complete agenesis of anus

- uterus

- Bifid tongue

Heart-hand syndrome type 1 is more commonly known as Holt–Oram syndrome. Is the most prevalent form of heart-hand syndrome.

It is an autosomal dominant disorder that affects bones in the arms and hands (the upper limbs) and may also cause heart problems. The syndrome includes an absent radial bone in the arms, an atrial septal defect, and a first degree heart block.

It is characterized by developmental defects including cryptophthalmos (where the eyelids fail to separate in each eye), and malformations in the genitals (such as micropenis, cryptorchidism or clitoromegaly). Congenital malformations of the nose, ears, larynx and renal system, as well as mental retardation, manifest occasionally. Syndactyly (fused fingers or toes) has also been noted.

Of those fetuses that do survive to gestation and subsequent birth, common abnormalities may include:

- Nervous system

- Intellectual disability and motor disorder

- Microcephaly

- Holoprosencephaly (failure of the forebrain to divide properly).

- Structural eye defects, including microphthalmia, Peters' anomaly, cataract, iris or fundus (coloboma), retinal dysplasia or retinal detachment, sensory nystagmus, cortical visual loss, and optic nerve hypoplasia

- Meningomyelocele (a spinal defect)

- Musculoskeletal and cutaneous

- Polydactyly (extra digits)

- Cyclopia

- Proboscis

- Congenital trigger digits

- Low-set ears

- Prominent heel

- Deformed feet known as rocker-bottom feet

- Omphalocele (abdominal defect)

- Abnormal palm pattern

- Overlapping of fingers over thumb

- Cutis aplasia (missing portion of the skin/hair)

- Cleft palate

- Urogenital

- Abnormal genitalia

- Kidney defects

- Other

- Heart defects (ventricular septal defect) (Patent Ductus Arteriosus)

- Dextrocardia

- Single umbilical artery

There is no specific treatment or cure for individuals affected with this type of syndrome, though some of the abnormal physical features may be surgically correctable.

There is a range of signs and symptoms including cleft lip or palate, mental retardation and various forms of ectodermal dysplasia. Additional symptoms may include fused eyelids, absent nails, delayed bone growth and dry skin. It is believed that this syndrome follows an autosomal dominant pattern of inheritance with incomplete penetrance, and caused by a mutation affecting the TP63 gene. It has been suggested that this syndrome, AEC syndrome and Rapp–Hodgkin syndrome may be variations of the same disease.

The most striking sign of Timothy syndrome is the co-occurrence of both syndactyly (~0.03% of births) and long QT syndrome (1% per year) in a single patient. Other common symptoms of Timothy syndrome are cardiac arrhythmia (94%), heart malformations (59%), autism or an autism spectrum disorder (80% who survive long enough for evaluation). Facial dysmorphologies such as flattened noses also occur in approximately half of patients. Children with this disorder have small teeth which, due to poor enamel coating, are prone to dental cavities and often require removal. The average age of death due to complications of these symptoms is 2.5 years.

Atypical Timothy syndrome has largely the same symptoms as the classical form. Differences in the atypical form are the lack of syndactyly, the presence of musculoskeletal problems (particularly hyperflexible joints), and atrial fibrillation. Patients with atypical Timothy syndrome also have more facial deformities, including protruding foreheads and tongues. Finally, one patient with atypical Timothy syndrome had a body development discrepancy wherein her upper body was normally developed (that of a 6-year-old) while her lower half resembled a 2- or 3-year-old.

Children with Timothy syndrome tend to be born via caesarean section due to fetal distress.

Heart-hand syndromes are a group of rare diseases that manifest with both heart and limb deformities.

, known heart-hand syndromes include Holt–Oram syndrome, Berk–Tabatznik syndrome, heart-hand syndrome type 3, brachydactyly-long thumb syndrome, patent ductus arteriosus-bicuspid aortic valve syndrome and heart hand syndrome, Slovenian type.

Multiple hamartoma syndrome is a syndrome characterized by more than one hamartoma.

It is sometimes equated with Cowden syndrome. However, MeSH also includes Bannayan–Zonana syndrome (that is, Bannayan–Riley–Ruvalcaba syndrome) and Lhermitte–Duclos disease under this description. Some articles include Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome, and at least some forms of Proteus syndrome and Proteus-like syndrome under the umbrella term PTEN hamartoma tumor syndromes (PHTS).

The hearing loss associated with Stickler syndrome can be progressive and usually involves the high frequencies. Sensorineural hearing loss has been reported in as many as 100% and as low as 20% of affected individuals. A conductive loss due to otitis can magnify an existing sensorineural loss and is a frequent problem for children with Stickler or Marshall Syndrome.

The most severe problem associated with Stickler syndrome is Pierre Robin syndrome. This refers to a cleft palate resulting from a very small lower jaw. During early fetal life, the roof of the mouth is normally open and the sides of the palate have to come together to close. If the jaw is too small, there is not enough room for the tongue which is then pushed up and gets in the way of the closing palate. Sometimes the chin is so small the baby has problems with eating and breathing if the tongue blocks the back of the throat. Cleft palate is found less frequently in Marshall Syndrome than in Stickler syndrome but still more frequently than in the general population.

The facial features of Marshall Syndrome include a flat midface, the appearance of large eyes, short upturned nose, and a round face. The facial features of Stickler syndrome are less prominent but include a rather long flat face, and depressed nasal bridge.

Fraser syndrome (also known as Meyer-Schwickerath's syndrome, Fraser-François syndrome, or Ullrich-Feichtiger syndrome) is an autosomal recessive congenital disorder. Fraser syndrome is named for the geneticist George R. Fraser, who first described the syndrome in 1962.

One of the most prominent and visible symptoms of Nevo Syndrome is the prenatal overgrowth, which continues into the infant and toddler stage. This excessive weight gain can be attributed to the low concentrations of growth hormone and insulin growth factor that are normally present to regulate weight gain. Other common symptoms associated with Nevo Syndrome are the outward wrist-drop, edema in hands and feet, undescended testes, low-set ears, hypotonia, the presence of low muscle tone in children, and long tapered fingers, and a highly arched palate.

Bannayan–Riley–Ruvalcaba syndrome is associated with enlarged head and benign mesodermal hamartomas (multiple hemangiomas, and intestinal polyps). Dysmorphy as well as delayed neuropsychomotor development can also be present. The head enlargement does not cause widening of the ventricles or raised intracranial pressure; these individuals have a higher risk of developing tumors, as the gene involved in BRRs is phosphatase and tensin homologue.

Some individuals have thyroid issues consistent with multinodular goiter, thyroid adenoma, differentiated non-medullary thyroid cancer,

most lesions are slowly growing. Visceral as well as intracranial involvement may occur in some cases, and can cause bleeding and symptomatic mechanical compression

The syndrome is a rare clinical disorder.

- Physical

- Overgrowth

- Accelerated skeletal maturation

- Dysmorphic facial features

- Prominent eyes

- Bluish sclerae

- Coarse eyebrows

- Upturned nose

- Radiologic examination

- Accelerated osseous maturation

- Phalangeal abnormalities

- Tubular thinning of the long bones

- Skull abnormalities

- Mental

- Often associated with intellectual disability (of variable degree)

Pashayan syndrome also known as Pashayan–Prozansky Syndrome, and blepharo-naso-facial syndrome is a rare syndrome. Facial abnormalities characterise this syndrome as well as malformation of extremities. Specific characteristics would be a bulky, flattened nose, where the face has a mask like appearance and the ears are also malformed.

A subset of Pashayan syndrome has also been described, known as "cerebrofacioarticular syndrome", "Van Maldergem syndrome'" or "Van Maldergem–Wetzburger–Verloes syndrome". Similar symptoms are noted in these cases as in Pashayan syndrome.

Timothy syndrome is a rare autosomal dominant disorder characterized by physical malformations, as well as neurological and developmental defects, including heart QT-prolongation, heart arrhythmias, structural heart defects, syndactyly (webbing of fingers and toes) and autism spectrum disorders.

Timothy syndrome often ends in early childhood death.

Sufferers usually have long, thin fingers and toes with contractures preventing straightening and limiting movement. Contractures also affect hips, elbows, knees and ankles. They also have unusual external ears that appear crumpled. Contractures may be present from birth and may appear as a club foot. Long bone fractures may also form a part of the syndrome, though the evidence for this is limited to the case report level.