The most common symptoms of Williams syndrome are heart defects and unusual facial features. Other symptoms include failure to gain weight appropriately in infancy (failure to thrive) and low muscle tone. Individuals with Williams syndrome tend to have widely spaced teeth, a long philtrum, and a flattened nasal bridge.

Most individuals with Williams syndrome are highly verbal relative to their IQ, and are overly sociable, having what has been described as a "cocktail party" type personality. Individuals with WS hyperfocus on the eyes of others in social engagements.

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.

Zamzam–Sheriff–Phillips syndrome is a rare autosomal recessive congenital disorder. It is characterized by aniridia, ectopia lentis, abnormal upper incisors and intellectual disability. Not a lot of research has been undertaken of this particular disease so thus far there is no known gene that affects this condition. However it has been hypothesised that the symptoms described are found at a particular gene, though intellectual disability is believed to be due to a different genetic cause.

Consanguinuity (intermarrying among relatives such as cousins), often associated with autosomal recessive inheritance, has been attributed to the inheritance of this disease.

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 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)

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.

Little is known about the natural history of Roberts syndrome due to its wide clinical variability. The prognosis of the disease depends on the malformations, as the severity of the malformations correlates with survival. The cause of death for most fatalities of Roberts syndrome have not been reported; however, five deaths were reportedly due to infection.

The following are observations that have been made in individuals with cytogenetic findings of PCS/HR or ESCO2 mutations:

- The symptom of prenatal growth retardation is the most common finding and can be moderate to severe. Postnatal growth retardation can also be moderate to severe and correlates with the degree of severity of limb and craniofacial malformations.

- In limb malformations, the upper limbs are typically more severely affected than the lower limbs. There have been many cases of only upper limb malformation.

- In hand malformations, the thumb is most often affected, followed by the fifth finger (the little finger). In severe cases, the patient may only have three fingers and in rare cases only one.

- In craniofacial malformations, mildly affected individuals will have no abnormalities of the palate. The most severely affected will have a fronto-ethmoid-nasal-maxillary encephalocele.

- The severity of limb malformations and craniofacial malformations is correlated.

- Other abnormalities can occur in different parts of the body, including:

- Heart- atrial septal defects, ventricular septal defects, patent ductus arteriosus

- Kidneys- polycystic kidney, horseshoe kidney

- Male Genitals- enlarged penis, cryptorchidism

- Female Genitals- enlarged clitoris

- Hair- sparse, silvery-blonde scalp hair

- Cranial Nerve Paralysis, Moyamoya disease, Stroke, Intellectual disability

Individuals with Williams syndrome experience many cardiac problems, commonly heart murmurs and the narrowing of major blood vessels as well as supravalvular aortic stenosis. Other symptoms may include gastrointestinal problems, such as severe or prolonged colic, abdominal pain and diverticulitis, nocturnal enuresis (bed wetting) and urinary difficulties, dental irregularities and defective tooth enamel, as well as hormone problems, the most common being high blood calcium. Hypothyroidism has been reported to occur in children, although there is no proof of it occurring in adults; adults with WS have a higher risk of developing type 2 diabetes, with some cases apparent as young as 21 years old.

Individuals with Williams syndrome often have hyperacusia and phonophobia which resembles noise-induced hearing loss, but this may be due to a malfunctioning auditory nerve. However, individuals with WS can also tend to demonstrate a love of music, and they appear significantly more likely to possess absolute pitch. There also appears to be a higher prevalence of left-handedness and left-eye dominance.

Ophthalmologic issues are common in Williams syndrome. Up to 75% of subjects in some studies have strabismus (ocular misalignment), particularly esotropia, due to inherent subnormal binocular visual function

and cognitive deficits in visuospatial construction. Individuals with Williams syndrome have problems with visual processing, but this is related to difficulty in dealing with complex spatial relationships rather than depth perception per se.

Nevo Syndrome is a rare autosomal recessive disorder that usually begins during the later stages of pregnancy. Nevo Syndrome is caused by a NSD1 deletion, which encodes for methyltransferase involved with chromatin regulation. The exact mechanism as to how the chromatin is changed is unknown and still being studied. Nevo Syndrome is an example of one of about twelve overgrowth syndromes known today. Overgrowth syndromes are characterized with children experiencing a significant overgrowth during pregnancy and also excessive postnatal growth. Studies concerning Nevo Syndrome have shown a similar relation to Ehlers-Danlos syndrome, a connective tissue disorder. Nevo Syndrome is associated with kyphosis, an abnormal increased forward rounding of the spine, joint laxity, postpartum overgrowth, a highly arched palate, undescended testes in males, low-set ears, increased head circumference, among other symptoms.

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.

The following is a list of symptoms that have been associated with Roberts syndrome:

- Bilateral Symmetric Tetraphocomelia- a birth defect in which the hands and feet are attached to shortened arms and legs

- Prenatal Growth Retardation

- Hypomelia (Hypoplasia)- the incomplete development of a tissue or organ; less drastic than aplasia, which is no development at all

- Oligodactyly- fewer than normal number of fingers or toes

- Thumb Aplasia- the absence of a thumb

- Syndactyly- condition in which two or more fingers (or toes) are joined together; the joining can involve the bones or just the skin between the fingers

- Clinodactyly- curving of the fifth finger (little finger) towards the fourth finger (ring finger) due to the underdevelopment of the middle bone in the fifth finger

- Elbow/Knee Flexion Contractures- an inability to fully straighten the arm or leg

- Cleft Lip- the presence of one or two vertical fissures in the upper lip; can be on one side (unilateral) or on both sides (bilateral)

- Cleft Palate- opening in the roof of the mouth

- Premaxillary Protrusion- upper part of the mouth sticks out farther than the lower part of the mouth

- Micrognathia- small chin

- Microbrachycephaly- smaller than normal head size

- Malar Hypoplasia- underdevelopment of the cheek bones

- Downslanting Palpebral Fissures- the outer corners of the eyes point downwards

- Ocular Hypertelorism- unusually wide-set eyes

- Exophthalmos- a protruding eyeball

- Corneal Clouding- clouding of the front-most part of the eye

- Hypoplastic Nasal Alae- narrowing of the nostrils that can decrease the width of the nasal base

- Beaked Nose- a nose with a prominent bridge that gives it the appearance of being curved

- Ear Malformations

- Intellectual disability

- Encephalocele (only in severe cases)- rare defect of the neural tube characterized by sac-like protrusions of the brain

Mortality is high among those severely affected by Roberts syndrome; however, mildly affected individuals may survive to adulthood

Males with 48, XXXY can have average or tall stature, which becomes more prominent in adulthood. Facial dysmorphism is common in males with 48, XXXY and can include increased distance between the eyes (hypertelorism), skin folds of the upper eyelid (epicanthal folds), up-slanting opening between the eyelids (palpebral fissures) and hooded eyelids. Other physical features include the fifth finger or "pinky" to be bent inwards towards the fourth finger (clinodactyly), short nail beds, flat feet, double jointedness (hyperextensibility) and prominent elbows with cubitus varus where the arm rests closer to the body. Musculoskeletal features may include congentical elbow dislocation and the limited ability of the feet to roll inwards while walking and upon landing. Micropenis is another common symptom of this syndrome.

Individuals affected with XXXY are also prone to developing Taurodontism, which often presents early in life, and can be an early indicator of XXY syndrome. Those with this syndrome are also prone to hip dysplasia, and other joint abnormalities. An individual’s symptoms vary due to differing androgen deficiencies, and also with alter with age. Prepubescent boys with XXXY syndrome may not differ in physical appearance from a child without the syndrome. This is likely because androgen levels do not differ among pre-pubescent boys, but a difference does arise as puberty progresses. Those with XXXY syndrome may also experience feminine distribution of adipose tissue, and gynecomastia may also be present. Tall stature is more likely to appear in adolescence, when androgen levels begin to differ between those with XXXY syndrome and those that do not have it.

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.

Patau syndrome is a syndrome caused by a chromosomal abnormality, in which some or all of the cells of the body contain extra genetic material from chromosome 13. The extra genetic material disrupts normal development, causing multiple and complex organ defects.

This can occur either because each cell contains a full extra copy of chromosome 13 (a disorder known as trisomy 13 or trisomy D), or because each cell contains an extra partial copy of the chromosome (i.e., Robertsonian translocation) or because of mosaic Patau syndrome. Full trisomy 13 is caused by nondisjunction of chromosomes during meiosis (the mosaic form is caused by nondisjunction during mitosis).

Like all nondisjunction conditions (such as Down syndrome and Edwards syndrome), the risk of this syndrome in the offspring increases with maternal age at pregnancy, with about 31 years being the average. Patau syndrome affects somewhere between 1 in 10,000 and 1 in 21,700 live births.

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.

In the beginning, medical officials defined ABCD syndrome by the four key characteristics of the syndrome. In the first case study of the Kurdish girl, researches described her as having "albinism and a black lock at the right temporo-occipital region along Blaschko lines, her eyelashes and brows were white, the irises in her eyes appeared to be blue, she had spots of retinal depigmentation, and she did not react to noise." The albinism is interesting in this diagnosis because the skin of an affected individual is albino pale besides the brown patches of mispigmented skin. The "black locks" described and seen in clinical pictures of the infants are thick patches of black hair above the ears that form a half circle reaching to the other ear to make a crest shape.

As identified in this first case study and stated in a dictionary of dermatologic syndromes, ABCD syndrome has many notable features, including "snow white hair in patches, distinct black locks of hair, skin white except brown macules, deafness, irises gray to blue, nystagmus, photophobia, poor visual activity, normal melanocytes in pigmented hair and skin, and absent melanocytes in areas of leukoderma." Individuals have the blue/gray irises typical of people affected by blindness. The C of ABCD syndrome is what distinguishes this genetic disorder from BADS and it involves cell migration disorder of the neurocytes of the gut. This characteristic occurs when nerve cells do not function correctly in the gut, which results in aganglionosis: The intestines’ failure to move food along the digestive tract. Deafness or being unresponsive to noise due to very low quality of hearing was reported in every case of ABCD syndrome. The characteristics of ABCD syndrome are clearly evident in an inflicted individual.

No longer considered a separate syndrome, ABCD syndrome is today considered to be a variation of Shah-Waardenburg type IV. Waardenburg syndrome (WS) is described as "the combination of sensorineural hearing loss, hypopigmentation of skin and hair, and pigmentary disturbances of the irides." Hearing loss and deafness, skin mispigmentation and albinism, and pigmentary changes in irises are the similarities between WS and ABCD. According to a dictionary of dermatologic syndromes, Waardenburg syndrome has many notable features, including "depigmentation of hair and skin – white forelock and premature graying of hair, confluent thick eyebrows, heterochromic irides or hypopigmentation of iris, laterally displaced inner canthi, congenital sensorineural deafness, broad nasal root, autosomal dominant disorder, and other associated findings, including black forelocks."

Neurological effects are believed to be more severe as the number of extra X chromosomes increases; a male with 48, XXXY is likely to have more severe symptoms than a male with Klinefelter syndrome. Developmental delays are common in infancy and childhood. Expected symptoms include speech delays, motor delays, and hypotonia (lack of muscle tone), also known as floppy baby syndrome.Individuals with XXXY syndrome exhibit cognitive and behavioral problems.

Patients typically show altered adaptive behavior, which is the ability of an individual to demonstrate essential living skills, including: social skills, community living, safety, functional use of academic skills and self-care. People with XXXY syndrome were found to score significantly less in the domains of daily living skills and communication compared to XXYY, and XXY individuals. This means that they typically demonstrate little ability in the domains of self-care, social skills, safety, application of academic skills, and responsibility.

Individuals with this syndrome also experience emotional symptoms such as anxiety symptoms, obsessive-compulsive behaviors, behavioral dysregulational and emotional immaturity. People with this syndrome typically have an IQ in the range of 40-60, where the average IQ range is 95-110. They also experience language-based learning disabilities that can affect their communication with others. Those with XXXY syndrome tend to display less externalizing and internalizing behaviors compared to those with 48, XXYY syndrome, which may have a positive effect on their social functioning. These individuals may also have increased vulnerability for autistic features. Changes in testosterone as well as androgen deficits may contribute to these individuals’ social behaviors that put them at increased risk for autistic features.

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.

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.

Psychiatric syndromes often called "psychopathological syndromes" (psychopathology is a psychic dysfunction occurring in mental disorder, also it's the study of the origin, diagnosis, development, and treatment of mental disorders).

In Russia those psychopathological syndromes are used in modern clinical practice and described in psychiatric literature in the details: asthenic syndrome, obsessive syndrome, emotional syndromes (for example, manic syndrome, depressive syndrome), Cotard's syndrome, catatonic syndrome, hebephrenic syndrome, delusional and hallucinatory syndromes (for example, paranoid syndrome, paranoid-hallucinatory syndrome, Kandinsky-Clérambault's syndrome also known as syndrome of psychic automatism, hallucinosis), paraphrenic syndrome, psychopathic syndromes (includes all personality disorders), clouding of consciousness syndromes (for example, twilight clouding of consciousness, amential syndrome also known as amentia, delirious syndrome, stunned consciousness syndrome, oneiroid syndrome), hysteric syndrome, neurotic syndrome, Korsakoff's syndrome, hypochondriacal syndrome, paranoiac syndrome, senestopathic syndrome, encephalopathic syndrome.

There are some examples of the psychopathological syndromes used in modern Germany: psychoorganic syndrome, depressive syndrome, paranoid-hallucinatory syndrome, obsessive-compulsive syndrome, autonomic syndrome, hostility syndrome, manic syndrome, apathy syndrome.

Also well known Münchausen syndrom, Ganser syndrome, neuroleptic-induced deficit syndrome, olfactory reference syndrome.

Marshall-Smith Syndrome, discovered in 1971 (Marshall, Graham, Scott, Boner, & Smith), is characterized by unusual accelerated skeletal maturation (usually starting before birth) and symptoms like conspicuous physical characteristics, respiratory difficulties, and mental retardation. Cases described in the literature show a clinical variability regarding related symptoms. For instance, respiratory difficulties are ranging from absent to severe difficulties.

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.