People with this condition are short-statured from birth, with a very short trunk and shortened limbs. Their hands and feet, however, are usually average-sized. Curvature of the spine (scoliosis and lumbar lordosis) may be severe and can cause problems with breathing. Changes in the spinal bones (vertebrae) in the neck may also increase the risk of spinal cord damage. Other skeletal signs include flattened vertebrae (platyspondyly), severe protrusion of the breastbone (pectus carinatum), a hip joint deformity in which the upper leg bones turn inward (coxa vara), and a foot deformity known as clubfoot.

Affected individuals have mild and variable changes in their facial features. The cheekbones close to the nose may appear flattened. Some infants are born with an opening in the roof of the mouth, which is called a cleft palate. Severe nearsightedness (high myopia) and detachment of the retina (the part of the eye that detects light and color) are also common.

The following are symptoms characteristic with individuals having the disorder. Individuals may display some, most, or all of these symptoms throughout the course of their life, though symptoms may vary with each patient.

- Abnormal hair (coarse, thick, brittle)

- Calvarial hypomineralization (soft skull)

- Y-shaped cataracts by 1–2 years of age

- Skeletal defects

- Hypertelorism (wide-set eyes)

- Facial dysmorphisms

- Late-closing fontanels

- Abnormal accumulation of proteins in the endoplasmic reticulum

- Scoliosis

- Broad forehead, nose

- Missing, small teeth or abnormal teeth positioning

- Poor skull calcification

- Flat foot

- Motor delay

- Abnormal vertebrae

- Prominent forehead and brow

- High nose bridge

- Capillary hemangioma

- Delayed tooth eruption

- Long upper lip groove

- Large mouth

- High arched palate

- Narrow hips and rib cage

- Thin lips

- Narrow and sloping shoulders

- Hyperpigmentation

- Hyperextensible joints

Onset of the disease is in neonatal development and infancy, and symptoms tend to become evident soon after birth.

Because collagen plays an important role in the development of the body, people with Kniest Dysplasia will typically have their first symptoms at birth. These symptoms can include:.

- Musculoskeletal Problems

- Short limbs

- Shortened body trunk

- Flattened bones in the spine

- kyphoscoliosis

- Scoliosis (Lateral curvature of the spine)

- Early development of arthritis

- Respiratory problems

- Respiratory tract infection

- Difficulty breathing

- Eye problems

- Severe myopia (near-sightedness)

- Cataract (cloudiness in the lens of the eye)

- Hearing problems

- progressive hearing loss

- ear infections

Most symptoms are chronic and will continue to worsen as the individual ages. It is essential to have regular checkups with general doctors, orthopedist, ophthalmologists, and/or otorhinolaryngologists. This will help to detect whether there are any changes that could cause concern.

Fingernails and toenails may be thick, abnormally shaped, discolored, ridged, slow-growing, or brittle. The cuticles may be prone to infections.

The skin may be lightly pigmented. Skin sustaining injury may grow back permanently hypo-pigmented. In some cases, red or brown pigmentation may be present. Skin can be prone to rashes or infections and can be thick over the palms and soles. Care must be taken to prevent cracking, bleeding, and infection.

This condition is also characterized by an unusual clubfoot with twisting of the metatarsals, inward- and upward-turning foot, tarsus varus, and inversion adducted appearances. Furthermore, they classically present with scoliosis (progressive curvature of the spine), and unusually positioned thumbs (hitchhiker thumbs). About half of infants with diastrophic dysplasia are born with an opening in the roof of the mouth called a cleft palate. Swelling of the external ears is also common in newborns and can lead to thickened, deformed ears.

The signs and symptoms of diastrophic dysplasia are similar to those of another skeletal disorder called atelosteogenesis, type 2; however diastrophic dysplasia tends to be less severe.

Fibrochondrogenesis is a congenital disorder presenting several features and radiological findings, some which distinguish it from other osteochondrodysplasias. These include: fibroblastic dysplasia and fibrosis of chondrocytes (cells which form cartilage); and flared, widened

long bone metaphyses (the portion of bone that grows during childhood).

Other prominent features include dwarfism, shortened ribs that have a appearance, micrognathism (severely underdeveloped jaw), macrocephaly (enlarged head), thoracic hypoplasia (underdeveloped chest), enlarged stomach, platyspondyly (flattened spine), and the somewhat uncommon deformity of tongue (in which the tongue appears split, resembling that of a reptile).

People with spondyloepiphyseal dysplasia are short-statured from birth, with a very short trunk and neck and shortened limbs. Their hands and feet, however, are usually average-sized. This type of dwarfism is characterized by a normal spinal column length relative to the femur bone. Adult height ranges from 0.9 meters (35 inches) to just over 1.4 meters (55 inches). Curvature of the spine (kyphoscoliosis and lordosis) progresses during childhood and can cause problems with breathing. Changes in the spinal bones (vertebrae) in the neck may also increase the risk of spinal cord damage. Other skeletal signs include flattened vertebrae (platyspondyly), a hip joint deformity in which the upper leg bones turn inward (coxa vara), and an inward- and downward-turning foot (called clubfoot). Decreased joint mobility and arthritis often develop early in life. Medical texts often state a mild and variable change to facial features, including cheekbones close to the nose appearing flattened, although this appears to be unfounded. Some infants are born with an opening in the roof of the mouth, which is called a cleft palate. Severe nearsightedness (high myopia) is sometimes present, as are other eye problems that can affect vision such as detached retinas. About one-quarter of people with this condition have mild to moderate hearing loss.

EEM syndrome exhibits a combination of prominent symptoms and features. These include: ectodermal dysplasia (systemic malformations of ectodermal tissues), ectrodactyly ("lobster claw" deformity in the hands and feet), macular dystrophy (a progressive eye disease), syndactyly (webbed fingers or toes), hypotrichosis (a type of hair-loss), and dental abnormalities (hypodontia).

Spondyloepimetaphyseal dysplasia, Strudwick type is an inherited disorder of bone growth that results in dwarfism, characteristic skeletal abnormalities, and problems with vision. The name of the condition indicates that it affects the bones of the spine (spondylo-) and two regions near the ends of bones (epiphyses and metaphyses). This type was named after the first reported patient with the disorder. Spondyloepimetaphyseal dysplasia, Strudwick type is a subtype of collagenopathy, types II and XI.

The signs and symptoms of this condition at birth are very similar to those of spondyloepiphyseal dysplasia congenita, a related skeletal disorder. Beginning in childhood, the two conditions can be distinguished in X-ray images by changes in areas near the ends of bones (metaphyses). These changes are characteristic of spondyloepimetaphyseal dysplasia, Strudwick type.

Most people with hypohidrotic ectodermal dysplasia have a reduced ability to sweat (hypohidrosis) because they have fewer sweat glands than normal or their sweat glands do not function properly. Sweating is a major way that the body controls its temperature; as sweat evaporates from the skin, it cools the body. An inability to sweat can lead to a dangerously high body temperature (hyperthermia) particularly in hot weather. In some cases, hyperthermia can cause life-threatening medical problems.

Affected individuals tend to have sparse scalp and body hair (hypotrichosis). The hair is often light-coloured, brittle, and slow-growing. This condition is also characterized by absent teeth (hypodontia) or teeth that are malformed. The teeth that are present are frequently small and pointed.

Hypohidrotic ectodermal dysplasia is associated with distinctive facial features including a prominent forehead, thick lips, and a flattened bridge of the nose. Additional features of this condition include thin, wrinkled, and dark-colored skin around the eyes; chronic skin problems such as eczema; and a bad-smelling discharge from the nose (ozena).

Hypohidrotic ectodermal dysplasia is the most common form of ectodermal dysplasia in humans. It is estimated to affect at least 1 in 17,000 people worldwide.

Infants born with this condition have very short arms and legs, a narrow chest, and a prominent, rounded abdomen. This disorder is also characterized by an opening in the roof of the mouth (cleft palate), distinctive facial features, an inward- and downward-turning foot (clubfoot), and unusually positioned thumbs (hitchhiker thumbs).

The signs and symptoms of atelosteogenesis, type 2, are similar to those of another skeletal disorder called diastrophic dysplasia. Atelosteogenesis, type 2 tends to be more severe, however.

Prenatal and neonatal diagnosis of boomerang dysplasia includes several prominent features found in other osteochondrodysplasias, though the "boomerang" malformation seen in the long bones is the delineating factor.

Featured symptoms of boomerang dysplasia include: dwarfism (a lethal type of infantile dwarfism caused by systemic bone deformities), underossification (lack of bone formation) in the limbs, spine and ilium (pelvis); proliferation of multinucleated giant-cell chondrocytes (cells that produce cartilage and play a role in skeletal development - chondrocytes of this type are rarely found in osteochondrodysplasias), brachydactyly (shortened fingers) and (undersized, shortened bones).

The characteristic "boomerang" malformation presents intermittently among random absences of long bones throughout the skeleton, in affected individuals. For example, one individual may have an absent radius and fibula, with the "boomerang" formation found in both ulnas and tibias. Another patient may present "boomerang" femora, and an absent tibia.

Severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN), is a very rare genetic disorder. This disorder is one that affects bone growth and is characterized by skeletal, brain, and skin abnormalities. Those affected by the disorder are severely short in height and commonly possess shorter arms and legs. In addition, the bones of the legs are often bowed and the affected have smaller chests with shorter rib bones, along with curved collarbones. Other symptoms of the disorder include broad fingers and extra folds of skin on the arms and legs. Developmentally, many individuals who suffer from the disorder show a higher level in delays and disability. Seizures are also common due to structural abnormalities of the brain. Those affected may also suffer with apnea, the slowing or loss of breath for short periods of time.

Many of the features of SADDAN are similar to those seen in other skeletal disorders, specifically achondroplasia and thanatophoric dysplasia.

Achondroplasia is a form of short-limbed dwarfism. This type of dwarfism is caused by the inability of the cartilage of the skeleton to ossify and turn to bone. Acanthosis nigricans is a skin condition in which areas of the skin is of a dark and velvety discoloration, often seen in the body folds and creases such as the armpits, groin, and neck. Within those affected by SADDAN, acanthosis nigricans develops early on, usually in infancy or early childhood.

It's part of the mesomelic and rhizomelic skeletal dysplasias, primary bone diseases in which the short stature is due to a lack of complete bone development of the limb's long bones.

It's strictly related to another disease, the Léri–Weill dyschondrosteosis, of which it seems to be the homozygothic variant, clinically more severe (it differs from this disorder for the absence, in some cases, of the Madelung deformity too).

Clinically and radiologically the disease is characterized by severe shortening of long bones (limb's both proximal and median segments are affected), aplasia or severe hypoplasia of ulna and fibula, thickened and curved radius and tibia. These anomalies can cause deformities of the hands and feet. Hypoplasia of the mandible can also be present.

Diastrophic dysplasia (DTD) is an autosomal recessive dysplasia which affects cartilage and bone development. ("Diastrophism" is a general word referring to a twisting.) Diastrophic dysplasia is due to mutations in the "SLC26A2" gene.

Affected individuals have short stature with very short arms and legs and joint problems that restrict mobility.

Pure hair-nail type ectodermal dysplasia is a genetic mutation in the "hair matrix and cuticle keratin KRTHB5 gene" that causes ectodermal dysplasia of hair and nail type. Manifestations of this disorder include onychodystrophy and severe hypotrichosis. It represents as an autosomal dominant trait.

Autosomal recessive multiple epiphyseal dysplasia (ARMED), also called epiphyseal dysplasia, multiple, 4 (EDM4), multiple epiphyseal dysplasia with clubfoot or –with bilayered patellae, is an autosomal recessive congenital disorder affecting cartilage and bone development. The disorder has relatively mild signs and symptoms, including joint pain, scoliosis, and malformations of the hands, feet, and knees.

Some affected individuals are born with an inward- and downward-turning foot (a clubfoot). An abnormality of the kneecap called a double-layered patella is also relatively common. Although some people with recessive multiple epiphyseal dysplasia have short stature as adults, most are of normal height. The incidence is unknown as many cases are not diagnosed due to mild symptoms.

Lelis syndrome it is a genetic disorder, a rare condition with dermatological and dental findings characterized by the association of ectodermal dysplasia (hypotrichosis and hypohidrosis) with acanthosis nigricans. Other clinical features may include palmoplantar hyperkeratosis, nail dystrophy, intellectual deficit, disturbances of skin pigmentation (perioral and periorbital hyperpigmentation, vitiligo, and perinevic leukoderma) and hypodontia. Transmission is autosomal recessive.

Cartilage–hair hypoplasia (CHH), also known as McKusick type metaphyseal chondrodysplasia, is a rare genetic disorder. It is a highly pleiotropic disorder that clinically manifests by form of short-limbed dwarfism due to skeletal dysplasia, variable level of immunodeficiency and predisposition to malignancies in some cases. It was first reported in 1965 by McKusick et al. Actor Verne Troyer is affected with this form of dwarfism, as was actor Billy Barty, who was renowned for saying "The name of my condition is Cartilage Hair Syndrome Hypoplasia, but you can just call me Billy."

Spondyloepiphyseal dysplasia congenita (abbreviated to SED more often than SDC) is a rare disorder of bone growth that results in dwarfism, characteristic skeletal abnormalities, and occasionally problems with vision and hearing. The name of the condition indicates that it affects the bones of the spine (spondylo-) and the ends of bones (epiphyses), and that it is present from birth (congenital). The signs and symptoms of spondyloepiphyseal dysplasia congenita are similar to, but milder than, the related skeletal disorders achondrogenesis type 2 and hypochondrogenesis. Spondyloepiphyseal dysplasia congenita is a subtype of collagenopathy, types II and XI.

Being an extremely rare autosomal genetic disorder, differential diagnosis has only led to several cases since 1972. Initial diagnosis lends itself to facial abnormalities including sloping forehead, maxillary hypoplasia, nasal bridge depression, wide mouth, dental maloclusion, and receding chin. Electroencephalography (EEG), computed tomography (CT) scanning, and skeletal survey are further required for confident diagnosis. Commonly, diffuse cartilage calcification and brachytelephalangism are identified by X-radiation (X-ray), while peripheral pulmonary arterial stenosis, hearing loss, dysmorphic facies, and mental retardation are confirmed with confidence by the aforementioned diagnostic techniques.

Kniest Dysplasia is a rare form of dwarfism caused by a mutation in the COL2A1 gene on chromosome 12. The COL2A1 gene is responsible for producing type II collagen. The mutation of COL2A1 gene leads to abnormal skeletal growth and problems with hearing and vision. What characterizes kniest dysplasia from other type II Osteochondrodysplasia is the level of severity and the dumb-bell shape of shortened long tubular bones. This condition was first diagnosed by Dr. Wilhelm Kniest in 1952. Dr. Kniest noticed that his 50 year old patient was having difficulties with restricted joint mobility. The patient had a short stature and was also suffering from blindness. Upon analysis of the patient's DNA, Dr. Kniest discovered that a mutation had occurred at a splice site of the COL2A1 gene. This condition is very rare and occurs less than 1 in 1,000,000 people. Males and females have equal chances of having this condition. Currently, there is no cure for kniest dysplasia. Alternative names for Kniest Dysplasia can include Kniest Syndrome, Swiss Cheese Cartilage Syndrome, Kniest Chondrodystrophy, or Metatrophic Dwarfism Type II.

Hypohidrotic ectodermal dysplasia (also known as "anhidrotic ectodermal dysplasia", and "Christ-Siemens-Touraine syndrome") is one of about 150 types of ectodermal dysplasia in humans. Before birth, these disorders result in the abnormal development of structures including the skin, hair, nails, teeth, and sweat glands.