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.

Fibrochondrogenesis is quite rare. A 1996 study from Spain determined a national minimal prevalence for the disorder at 8 cases out of 1,158,067 live births.

A United Arab Emirates (UAE) University report, from early 2003, evaluated the results of a 5-year study on the occurrence of a broad range of osteochondrodysplasias. Out of 38,048 newborns in Al Ain, over the course of the study period, fibrochondrogenesis was found to be the most common of the recessive forms of osteochondrodysplasia, with a prevalence ratio of 1.05:10,000 births.

While these results represented the most common occurrence within the group studied, they do not dispute the rarity of fibrochondrogenesis. The study also included the high rate of consanguinous marriages as a prevailing factor for these disorders, as well as the extremely low rate of diagnosis-related pregnancy terminations throughout the region.

Life expectancy for individuals with hypochondroplasia is normal; the maximum height is about 147 cm or 4.8 ft.

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.

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.

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.

It can be associated with missense mutations in fibroblast growth factor receptor-3. It is inherited in an autosomal dominant manner.

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.

Fibrochondrogenesis is inherited in an autosomal recessive pattern. This means that the defective gene responsible for the disorder is located on an autosome, and two copies of the gene — one copy inherited from each parent — are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder each carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder. Currently, no specific genetic mutation has been established as the cause of fibrochondrogenesis.

Omphalocele is a congenital feature where the abdominal wall has an opening, partially exposing the abdominal viscera (typically, the organs of the gastrointestinal tract). Fibrochondrogenesis is believed to be related to omphalocele

type III, suggesting a possible genetic association between the two disorders.

Spondyloepiphyseal dysplasia congenita 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.

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

It is thought that chondrodystrophy is caused by an autosomal, recessive allele. To avoid a potential "lethal dose," both parents must submit to genetic testing. If a child is conceived with another carrier the outcome may be lethal, or the child may suffer from chondrodystrophy or dwarfism. This means that even though both parents are completely normal in height, the child will have one of the two types of skeletal dysplasia. Type 1 (short limb dysplasia), the more common of the two, is characterised by a long trunk and extremely shortened extremities. Type 2, short-trunk dysplasia, is characterised by a shortened trunk and normal size extremities. Those affected by chondrodystrophy may also experience metabolic and hormonal disorders, both of which may be monitored and controlled by hormonal injections.

Animals have been bred specifically to elicit chondrodystrophic traits for research purposes and to more easily allow animals to free-roam without escaping by, for example, jumping over ranch fences. One example of this is the Ancon sheep, which was first bred from a lamb born in 1791 with naturally occurring chondrodystrophy.

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.

Patients with CHH usually suffer from cellular immunodeficiency. In the study of 108 Finnish patients with CHH there was detected mild to moderate form of lymphopenia, decreased delayed type of hypersensitivity and impaired responses to phytohaemagglutinin. This leads to susceptibility to and, in some more severe cases, mortality from infections early in childhood. There has also been detected combined immunodeficiency in some patients

Patients with CHH often have increased predispositions to malignancies.

In terms of cause this disorder is transmitted as an autosomal dominant trait affecting the "FGFR3" gene on chromosome 4p16.3, there is currently no cure for this condition.

Mutations in the "Filamin B (FLNB)" gene cause boomerang dysplasia. FLNB is a cytoplasmic protein that regulates intracellular communication and signalling by cross-linking the protein actin to allow direct communication between the cell membrane and cytoskeletal network, to control and guide proper skeletal development. Disruptions in this pathway, caused by FLNB mutations, result in the bone and cartilage abnormalities associated with boomerang dysplasia.

Chondrocytes, which also have a role in bone development, are susceptible to these disruptions and either fail to undergo ossification, or ossify incorrectly.

FLNB mutations are involved in a spectrum of lethal bone dysplasias. One such disorder, atelosteogenesis type I, is very similar to boomerang dysplasia, and several symptoms of both often overlap.

Lenz–Majewski syndrome is a skin condition characterized by hyperostosis, craniodiaphyseal dysplasia, dwarfism, cutis laxa, proximal symphalangism, syndactyly, brachydactyly, mental retardation, enamel hypoplasia, and hypertelorism.

In 2013, whole-exome sequencing showed that a missense mutation resulting in overactive phosphatidylserine synthase 1 was the cause of LMS, making it the first known human disease to be caused by disrupted phosphatidylserine metabolism. The researchers suggested a link between the condition and bone metabolism.

Gene based therapy is being studied. In June 2015, BioMarin announced positive results of their Phase 2 study, stating that 10 children experienced a mean increase of 50% in their annualized growth velocity.

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.

Achondroplasia is one of 19 congenital conditions with similar presentations, such as osteogenesis imperfecta, multiple epiphyseal dysplasia tarda, achondrogenesis, osteopetrosis, and thanatophoric dysplasia. This makes estimates of prevalence difficult, with changing and subjective diagnostic criteria over time. One detailed and long-running study in the Netherlands found that the prevalence determined at birth was only 1.3 per 100,000 live births. Another study at the same time found a rate of 1 per 10,000.

Both average parents

1.) A couple already has a child with chondrodystrophy; the risk of inheritance for the next child to have the disorder is 0.1% (less than 1 in 1,000)

2.) The risk that the normal-statured child will have at least one offspring with this disorder is 0.01% (less than 1 in 10,000)

One parent with chondrodystrophy and one parent without

1.) One child with normal height; the probability of that child having offspring with chondrodystrophy is 0.01% (less than 1 in 10,000)

2.) One child with normal stature; the probability of the next having chondrodystrophy is 50% (1 in 2)

3.) One child with normal stature; the probability of the next not having chondrodystrophy is 50% (1 in 2)

Both parents with chondrodystrophy

1.) The probability of offspring affected by chondrodystrophy is 100% (4 in 4)

2.) The probability of offspring to be of normal size is 0% (0 in 4)

Parastremmatic dwarfism is apparent at birth, with affected infants usually being described as "stiff", or as "twisted dwarfs" when the skeletal deformities and appearance of dwarfism further present themselves. Skeletal deformities usually develop in the sixth to twelfth month of an infant's life. The deformities may be attributed to osteomalacia, a lack of bone mineralization.

"Achondroplasia" is a type of autosomal dominant genetic disorder that is the most common cause of dwarfism. Achondroplastic dwarfs have short stature, with an average adult height of 131 cm (4 feet, 3 inches) for males and 123 cm (4 feet, 0 inches) for females.

The prevalence is approximately 1 in 25,000 births.

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.

Many features of gerodermia osteodysplastica (GO) and another autosomal recessive form of cutis laxa, wrinkly skin syndrome (WSS, ""), are similar to such an extent that both disorders were believed to be variable phenotypes of a single disorder.

Several delineating factors, however, suggest that gerodermia osteodysplastica and wrinkly skin syndrome are distinct entities, but share the same clinic spectrum.

While the prevailing feature of wrinkly, loose skin is more localized with GO, it is usually systemic, yet eases in severity with age during the course of WSS. Also, as the fontanelles ("soft spots") are usually normal on the heads of infants with GO, they are often enlarged in WSS infants.

While WSS is associated with mutations of genes on chromosomes 2, 5, 7, 11 and 14; GO has been linked to mutations in the protein GORAB. A serum sialotransferrin type 2 pattern, also observed with WSS, is not present in GO patients.

But perhaps the most notable feature, differentiating GO from WSS and similar cutis laxa disorders, is the age-specific metaphyseal peg sometimes found in GO-affected long bone, near the knee. Not appearing until around age 4–5, then disappearing by physeal closure, this oddity of bone is thought to represent a specific genetic marker unique to GO and its effects on bone development.

Acromicric dysplasia is an extremely rare inherited disorder characterized by abnormally short hands and feet, growth retardation and delayed bone maturation leading to short stature. Most cases have occurred randomly for no apparent reason (sporadically). However, autosomal dominant inheritance has not been ruled out.

According to the disease database, Acromicric dysplasia is synonymous with Geleophysic dysplasia

(or Geleophysic Dwarfism) and Focal mucopolysaccharidosis.