All types of Griscelli syndrome have distinctive skin and hair coloring.

Type 1 is associated with eurological abnormalities. These include delayed development, intellectual disability, seizures, hypotonia and eye abnormalities.

Type 2 - unlike type 1 - is not associated primary neurological disease but is associated with an uncontrolled T lymphocyte expansion and macrophage activation syndrome. It is often associated with the hemophagocytic syndrome. This latter condition may be fatal in the absence of bone marrow transplantation.

Persons with type 3 have the typical light skin and hair coloring but are otherwise normal.

An alternative name of the condition, LEOPARD syndrome, is a mnemonic, originally coined in 1969, as the condition is characterized by some of the following seven conditions, the first letters of which spell LEOPARD, along with the characteristic "freckling" of the skin, caused by the lentigines that is reminiscent of the large cat.

- Lentigines — Reddish-brown to dark brown macules (surface skin lesion) generally occurring in a high number (10,000+) over a large portion of the skin, at times higher than 80% coverage. These can even appear inside the mouth (buccal), or on the surface of the eye (scleral). These have irregular borders and range in size from 1 mm in diameter to café-au-lait spots, several centimeters in diameter. Also, some areas of vitiligo-like hypopigmentation may be observed.

- Electrocardiographic conduction abnormalities: Generally observed on an electrocardiograph as a bundle branch block.

- Ocular hypertelorism: Wideset eyes, which lead to a similar facial resemblance between patients. Facial abnormalities are the second highest occurring symptom after the lentigines. Abnormalities also include: broad nasal root, prognathism (protruding lower jaw), or low-set, possibly rotated, ears.

- Pulmonary stenosis: Narrowing of the pulmonary artery as it exits the heart. Other cardiac abnormalities may be present, including aortic stenosis, or mitral valve prolapse.

- Abnormal genitalia: usually cryptorchidism (retention of testicles in body) or monorchism (single testicle). In female patients, this presents as missing or single ovaries, much harder by nature to detect. Ultrasound imaging is performed at regular intervals, from the age of 1 year, to determine if ovaries are present.

- Retarded growth: Slow, or stunted growth. Most newborns with this syndrome are of normal birth weight and length, but will often slow within the first year.

- Deafness: Sensorineural (nerve deafness).

The presence of all of these hallmarks is not needed for a diagnosis. A clinical diagnosis is considered made when, with lentigines present there are 2 other symptoms observed, such as ECG abnormalities and ocular hypertelorism, or without lentigines, 3 of the above conditions are present, with a first-degree relative (i.e. parent, child, sibling) with a clinical diagnosis.

- Additional dermatologic abnormalities (axillary freckling, localized hypopigmentation, interdigital webbing, hyperelastic skin)

- Mild mental retardation is observed in about 30% of those affected with the syndrome

- Nystagmus (involuntary eye movements), seizures, or hyposmia (reduced ability to smell) has been documented in a few patients

- In 2004, a patient was reported with recurrent upper extremity aneurysms that required surgical repairs.

- In 2006, a NSML patient was reported with acute myelogenous leukemia.

Due to the rarity of the syndrome itself, it is hard to determine whether certain additional diseases are actually part of the syndrome. With a base population of possibly less than one thousand individuals, one or two outlying cases can skew the statistical population very quickly.

Nearly all individuals show multiple café au lait spots.Features common in neurofibromatosis - Lisch nodules, bone abnormalities, neurofibromas, optic pathway gliomas and malignant peripheral nerve sheath tumors - are absent in this condition Symptoms however, may include:

- Freckles

- Lipomas

- Macrocephaly

- Learning disabilities

- ADHD

- Developmental delay

Clinically, McKusick–Kaufman syndrome is characterized by a combination of three features: postaxial polydactyly, heart defects, and genital abnormalities:

- Vaginal atresia with hydrometrocolpos

- Double vagina and/or uterus.

- Hypospadias, chordee (a downward-curving penis), and undescended testes (cryptorchidism).

- ureter stenosis or ureteric atresia

Clinical expressions of PPS are highly variable, but include the following:

- Limb findings: an extensive web running from behind the knee down to the heel (90%), malformed toenails, and webbed toes.

- Facial findings: cleft palate with or without cleft lip (75%), pits in the lower lip (40%), and fibrous bands in the mouth known as syngnathia (25%).

- Genital findings (50%): hypoplasia of the labia majora, malformation of the scrotum, and cryptorchidism.

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

Griscelli syndrome type 2 (also known as "partial albinism with immunodeficiency") is a rare autosomal recessive syndrome characterized by variable pigmentary dilution, hair with silvery metallic sheen, frequent pyogenic infections, neutropenia, and thrombocytopenia.

Legius syndrome (LS) is an autosomal dominant condition characterized by cafe au lait spots. It was first described in 2007 and is often mistaken for neurofibromatosis type I (NF-1), it is caused by mutations in the SPRED1 gene, it is also known as Neurofibromatosis Type 1-like syndrome (NFLS). The condition is a RASopathy, developmental syndromes due to germline mutations in genes

Some or all of the following may be seen in someone with Gorlin syndrome:

1. Multiple basal-cell carcinomas of the skin

2. Keratocystic odontogenic tumor: Seen in 75% of patients and is the most common finding. There are usually multiple lesions found in the mandible. They occur at a young age (19 yrs average).

3. Rib and vertebrae anomalies

4. Intracranial calcification

5. Skeletal abnormalities: bifid ribs, kyphoscoliosis, early calcification of falx cerebri (diagnosed with AP radiograph)

6. Distinct faces: frontal and temporoparietal bossing, hypertelorism, and mandibular prognathism

7. Bilateral ovarian fibromas

8. 10% develop cardiac fibromas

Noonan syndrome with multiple lentigines (NSML) which is part of a group called Ras/MAPK pathway syndromes, is a rare autosomal dominant, multisystem disease caused by a mutation in the protein tyrosine phosphatase, non-receptor type 11 gene ("PTPN11"). The disease is a complex of features, mostly involving the skin, skeletal and cardiovascular systems, which may or may not be present in all patients. The nature of how the mutation causes each of the condition's symptoms is not well known; however, research is ongoing. It is a RASopathy.

Noonan syndrome with multiple lentigines is caused by a different missense mutation of the same gene. Noonan syndrome is fairly common (1:1,000 to 1:2,500 live births), and neurofibromatosis 1 (which was once thought to be related to NSML) is also common (1:3500); however, no epidemiological data exists for NSML.

McKusick–Kaufman syndrome is a genetic condition associated with MKKS.

The condition is named for Dr. Robert L. Kaufman and Victor McKusick. It is sometimes known by the abbreviation MKS. In infancy it can be difficult to distinguish between MKS and the related Bardet–Biedl syndrome, as the more severe symptoms of the latter condition rarely materialise before adulthood.

Popliteal pterygium syndrome (PPS) is an inherited condition affecting the face, limbs, and genitalia. The syndrome goes by a number of names including the "popliteal web syndrome" and, more inclusively, the "facio-genito-popliteal syndrome". The term PPS was coined by Gorlin "et al.." in 1968 on the basis of the most unusual anomaly, the popliteal pterygium (a web behind the knee).

Aneuploidy is often fatal, but in this case there is "X-inactivation" where the effect of the additional gene dosage due to the presence of extra X chromosomes is greatly reduced.

Much like Down syndrome, the mental effects of 49,XXXXY syndrome vary. Impaired speech and behavioral problems are typical. Those with 49,XXXXY syndrome tend to exhibit infantile secondary sex characteristics with sterility in adulthood and have some skeletal anomalies. Skeletal anomalies include:

- Genu valgum

- Pes cavus

- Fifth finger clinodactyly

The effects also include:

- Cleft palate

- Club feet

- Respiratory conditions

- Short or/and broad neck

- Low birth weight

- Hyperextensible joints

- Short stature

- Narrow shoulders

- Coarse features in older age

- Hypertelorism

- Epicanthal folds

- Prognathism

- Gynecomastia (rare)

- Muscular hypotonia

- Hypoplastic genitalia

- Cryptorchidism

- Congenital heart defects

- A very round face in infancy

Chief markers of Goldenhar syndrome are incomplete development of the ear, nose, soft palate, lip, and mandible on usually one side of the body. Additionally, some patients will have growing issues with internal organs, especially heart, kidneys, and lungs. Typically, the organ will either not be present on one side or will be underdeveloped. Note that while it is more usual for there to be problems on only one side, it has been known for defects to occur bilaterally (approximate incidence 10% of confirmed GS cases).

Other problems can include severe scoliosis (twisting of the vertebrae), limbal dermoids, and hearing loss (see hearing loss with craniofacial syndromes), and deafness or blindness in one or both ears/eyes, Granulosa cell tumors may be associated as well.

AMS has been described by multiple authors and institutions, and various definitions have been adopted. According to Newton et al., a scoring system allotting one point per feature establishes AMS with scores greater than or equal to 3. The features include: 1) two or more clinically atypical nevi, 2) more than 100 nevi in patients between 20 and 50 years of age, 3) more than 50 nevi in patients under 20 years of age or more than 50 years of age, 4) more than one nevus in buttocks or instep, 5) nevi on the anterior scalp, 6) one or more pigmented lesions in the iris.

The Classical (1990) definition uses the following criteria: 1) 100 or more melanocytic nevi, 2) one or more melanocytic nevi greater than or equal to 8mm in its largest diameter, and 3) one or more clinically atypical melanocytic nevi.

The National Institutes of Health (NIH) Consensus 1992 definition, which is still controversial, requires a family history of melanoma, in addition to a large number of melanocytic nevi (often greater than 50) and melanocytic nevi that present certain histological features.

FACES syndrome is a syndrome of unique facial features, anorexia, cachexia, eye and skin anomalies.

It is a rare disease and estimated to occur in less than 1 in 1 million people.

Orofaciodigital syndrome type 1 is diagnosed through genetic testing. Some symptoms of Orofaciodigital syndrome type 1 are oral features such as, split tongue, benign tumors on the tongue, cleft palate, hypodontia and other dental abnormalities. Other symptoms of the face include hypertelorism and micrognathia. Bodily abnormalities such as webbed, short, joined, or abnormally curved fingers and toes are also symptoms of Orofaciodigital syndrome type 1. The most frequent symptoms are accessory oral frenulum, broad alveolar ridges, frontal bossing, high palate, hypertelorism, lobulated tongue, median cleft lip, and wide nasal bridge. Genetic screening of the OFD1 gene is used to officially diagnose a patient who has the syndrome, this is detected in 85% of individuals who are suspected to have Orofaciodigital syndrome type 1.

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.

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.

In 1820 Norris reported the first case of what is now recognized as FAMMM (12). He described a 59-year-old man with melanoma, a high total body mole count, and family history of the same.

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

Café au lait spots are usually present at birth, permanent, and may grow in size or increase in number over time.

Cafe au lait spots are themselves benign and do not cause any illness or problems. However, they may be associated with syndromes such as Neurofibromatosis Type 1 and McCune-Albright syndrome.

The size and shape of the spots do not have any meaning or implications with regards to diagnosis of associated syndromes.

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.

Diagnosis is visual with measurement of spot size. The number of spots can have clinical significance for diagnosis of associated disorders such as Neurofibromatosis type I. Greater than or equal to 6 spots of at least 5mm in diameter in pre-pubertal children and at least 15mm in post-pubertal individuals is one of the major diagnostic criteria for NF1.

Goldenhar syndrome (also known as oculo-auriculo-vertebral (OAV) syndrome) is a rare congenital defect characterized by incomplete development of the ear, nose, soft palate, lip, and mandible. It is associated with anomalous development of the first branchial arch and second branchial arch. Common clinical manifestations include limbal dermoids, preauricular skin tags, and strabismus.

The term is sometimes used interchangeably with hemifacial microsomia, although this definition is usually reserved for cases without internal organ and vertebrae disruption.

It affects between 1/3,500 and 1/26,000 live births, with a male:female ratio of 3:2.