The frequency of this disorder is unknown, but it is very rare. Only a few families with the condition have been reported.

One person in every 100,000 is affected. Ollier disease is not normally diagnosed until toddler years because it is not very visible.

A recent article in 2015 reported a persistent notochord in a fetus at 23 weeks of gestation. The fetus had an abnormal spine, shortened long bones and a left clubfoot. After running postmortem tests and ultrasound, the researchers believed that the fetus suffered from hypochondrogenesis. Hypochondrogenesis is caused when type II collagen is abnormally formed due to a mutation in the COL2A1 gene. Normally, the cartilaginous notochord develops into the bony vertebrae in a human body. The COL2A1 gene results in malformed type II collagen, which is essential in the transition from collagen to bone. This is the first time that researchers found a persistent notochord in a human body due to a COL2A1 mutation.

Spondyloepimetaphyseal dysplasia is a genetic condition affecting the bones.

Types include:

- Spondyloepimetaphyseal dysplasia, Strudwick type

- Spondyloepiphyseal dysplasia congenita

- Spondyloepimetaphyseal dysplasia, Pakistani type

Ollier disease carries a high risk of skeletal, visceral and brain malignancy which occurs in approximately 25% of patients. Juvenile granulosa cell tumour has been associated with the disease. The incidence of secondary chondrosarcoma in Ollier disease is not known, but may be as high as 25%, pelvis and shoulder girdle being the commonest locations. A related disorder called Maffucci syndrome named after Angelo Maffucci is characterized by enchondromas associated with multiple hemangiomas which usually occur in the hands and feet. Maffucci syndrome carries a higher risk for cancer.

Spondyloperipheral dysplasia is an autosomal dominant disorder of bone growth. The condition is characterized by flattened bones of the spine (platyspondyly) and unusually short fingers and toes (brachydactyly). Some affected individuals also have other skeletal abnormalities, short stature, nearsightedness (myopia), hearing loss, and mental retardation. Spondyloperipheral dysplasia is a subtype of collagenopathy, types II and XI.

Opsismodysplasia is a type of skeletal dysplasia (a bone disease that interferes with bone development) first described by Zonana and associates in 1977, and designated under its current name by Maroteaux (1984). Derived from the Greek "opsismos" ("late"), the name "opsismodysplasia" describes a delay in bone maturation. In addition to this delay, the disorder is characterized by (short or undersized bones), particularly of the hands and feet, delay of ossification (bone cell formation), platyspondyly (flattened vertebrae), irregular metaphyses, an array of facial aberrations and respiratory distress related to chronic infection. Opsismodysplasia is congenital, being apparent at birth. It has a variable mortality, with some affected individuals living to adulthood. The disorder is rare, with an incidence of less than 1 per 1,000,000 worldwide. It is inherited in an autosomal recessive pattern, which means the defective (mutated) gene that causes the disorder is located on an autosome, and the disorder occurs when two copies of this defective gene are inherited. No specific gene has been found to be associated with the disorder. It is similar to spondylometaphyseal dysplasia, Sedaghatian type.

Kniest Dysplasia is an autosomal dominant condition. This means that the person only needs to have one copy of the mutated gene in order to have the condition. People with a family history are at a higher risk of having the disease than people with no family history. A random mutation in the gene can cause a person with no family history to also have the condition.

Spondyloepimetaphyseal dysplasia, Pakistani type is a form of spondyloepimetaphyseal dysplasia involving "PAPSS2" (also known as "ATPSK2"). The condition is rare.

Osteogenesis imperfecta is a rare condition in which bones break easily. There are multiple genetic mutations in different genes for collagen that may result in this condition. It can be treated with some drugs to promote bone growth, by surgically implanting metal rods in long bones to strengthen them, and through physical therapy and medical devices to improve mobility.

Opsismodysplasia is inherited in an autosomal recessive manner. This means the defective gene(s) responsible for the disorder is located on an autosome, and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder. Currently, no specific mutation in any gene has been found to cause the disorder.

It appears that the gene inositol polyphosphate phosphatase-like 1 is the cause of this condition in at least some cases.

Early journal reports of boomerang dysplasia suggested X-linked recessive inheritance, based on observation and family history. It was later discovered, however, that the disorder is actually caused by a genetic mutation fitting an autosomal dominant genetic profile.

Autosomal dominant inheritance indicates that the defective gene responsible for a disorder is located on an autosome, and only one copy of the gene is sufficient to cause the disorder, when inherited from a parent who has the disorder.

Boomerang dysplasia, although an autosomal dominant disorder, is "not" inherited because those afflicted do not live beyond infancy. They cannot pass the gene to the next generation.

Otospondylomegaepiphyseal dysplasia (OSMED) is an autosomal recessive disorder of bone growth that results in skeletal abnormalities, severe hearing loss, and distinctive facial features. The name of the condition indicates that it affects hearing (oto-) and the bones of the spine (spondylo-), and enlarges the ends of bones (megaepiphyses).

The features of OSMED are similar to those of another skeletal disorder, Weissenbacher-Zweymüller syndrome. Otospondylomegaepiphyseal dysplasia is a subtype of collagenopathy, types II and XI.

Radiographic features include delayed epiphyseal ossification at the hips and knees, platyspondyly with irregular end plates and narrowed joint spaces, diffuse early osteoarthritic changes (in the spine and hands), mild brachydactyly and mild metaphyseal abnormalities which predominantly involve the hips and knees.

Multiple epiphyseal dysplasia (MED) encompasses a spectrum of skeletal disorders, most of which are inherited in an autosomal dominant form. However, there is an autosomal recessive form.

Associated genes include COL9A1, COL9A2, COL9A3, COMP, and MATN3.

Types include:

Spondyloperipheral dysplasia is one of a spectrum of skeletal disorders caused by mutations in the "COL2A1" gene, located on chromosome 12q13.11-q13.2. The protein made by this gene forms type II collagen, a molecule found mostly in cartilage and in the clear gel that fills the vitreous humour (the eyeball). Type II collagen is essential for the normal development of bones and other connective tissues (the tissues that form the body's supportive framework).

Mutations in the "COL2A1" gene interfere with the assembly of type II collagen molecules. The protein made by the altered "COL2A1" gene cannot be used to make type II collagen, resulting in a reduced amount of this type of collagen in the body. Instead of forming collagen molecules, the abnormal protein builds up in cartilage cells (chondrocytes). These changes disrupt the normal development of bones, leading to the signs and symptoms of spondyloperipheral dysplasia.

The disorder is believed to be inherited in an autosomal dominant manner. This indicates that the defective gene responsible for the disorder is located on an autosome (chromosome 12 is an autosome), and only one copy of the defective gene is sufficient to cause the disorder, when inherited from a parent who has the disorder.

It is one of a spectrum of skeletal disorders caused by mutations in the "SLC26A2" gene. The protein encoded by this gene is essential for the normal development of cartilage and for its conversion to bone. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, but in adulthood this tissue continues to cover and protect the ends of bones and is present in the nose and external ears. Mutations in the SLC26A2 gene alter the structure of developing cartilage, preventing bones from forming properly and resulting in the skeletal problems characteristic of diastrophic dysplasia.

This condition is an autosomal recessive disorder, meaning that the defective gene is located on an autosome, and both parents must carry one copy of the defective gene in order to have a child born with the disorder. The parents of a child with an autosomal recessive disorder are usually not affected by the disorder.

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.

This condition is one of a spectrum of skeletal disorders caused by mutations in the "COL2A1" gene. The protein made by this gene forms type II collagen, a molecule found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). Type II collagen is essential for the normal development of bones and other connective tissues. Mutations in the "COL2A1" gene interfere with the assembly of type II collagen molecules, which prevents bones from developing properly and causes the signs and symptoms of this condition.

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder.

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.

Jansen's metaphyseal chondrodysplasia (JMC) is a disease that results from ligand-independent activation of the type 1 of the parathyroid hormone receptor (PTHR1), due to one of three reported mutations (activating mutation).

JMC is extremely rare, and as of 2007 there are fewer than 20 reported cases worldwide.

Platyspondylic lethal skeletal dysplasia, Torrance type is a severe disorder of bone growth. People with this condition have very short arms and legs, a small chest with short ribs, underdeveloped pelvic bones, and unusually short fingers and toes (brachydactyly). This disorder is also characterized by flattened spinal bones (platyspondyly) and abnormal curvature of the spine (lordosis).

As a result of these serious skeletal problems, many infants with platyspondylic lethal skeletal dysplasia, Torrance type are born prematurely, are stillborn, or die shortly after birth from respiratory failure. A few affected people with milder signs and symptoms have lived into adulthood, however.

This condition is one of a spectrum of skeletal disorders caused by mutations in the "COL2A1" gene. This gene provides instructions for making a protein that forms type II collagen. This type of collagen is found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). It is essential for the normal development of bones and other tissues that form the body's supportive framework (connective tissues).

Mutations in the "COL2A1" gene interfere with the assembly of type II collagen molecules, resulting in a reduced amount of this type of collagen in the body. Instead of forming collagen molecules, the abnormal "COL2A1" protein builds up in cartilage cells (chondrocytes). These changes disrupt the normal development of bones and other connective tissues, leading to the skeletal abnormalities characteristic of platyspondylic lethal skeletal dysplasia, Torrance type.

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

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.

The term thanatophoric is Greek for "death bearing". Children with this condition are usually stillborn or die shortly after birth from respiratory failure, however a small number of individuals have survived into childhood and a very few beyond. Survivors have difficulty breathing on their own and require respiratory support such as high flow oxygen through a canula or ventilator support via tracheostomy. There may also be evidence of spinal stenosis and seizures.

The oldest known living TD survivor is a 29-year-old female. One male lived to be 26 years old. Another male lived to age 20. TD survivor, Chrisopher Álvarez, 18, is Colombian living in New York. Two children with TD aged 10 and 12, a male and a female, are known in Germany. There is also a 6-year-old male living with TD and two 1-year old males.

Boomerang dysplasia is a lethal form of osteochondrodysplasia known for a characteristic congenital feature in which bones of the arms and legs are malformed into the shape of a boomerang. Death usually occurs in early infancy due to complications arising from overwhelming systemic bone malformations.

Osteochondrodysplasias are skeletal disorders that cause malformations of both bone and cartilage.