Osteochondrodysplasia

Osteochondrodysplasia or skeletal dysplasia is a general term for a disorder of the development (dysplasia) of bone ("osteo") and cartilage ("chondro").^[1]

Osteochondrodysplasias are rare diseases. About 1 in 5,000 babies are born with some type of skeletal dysplasia.^[2]

Types

Achondroplasia

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.^[3]

Cleidocranial dysostosis

Cleidocranial dysostosis is a general skeletal condition named for the collarbone (cleido-) and cranium deformities which people with it often have. Common features include:

• Partly or completely missing collarbones.
• A soft spot or larger soft area in the top of the head where the fontanelle failed to close.
• Bones and joints are underdeveloped.
• The permanent teeth include supernumerary teeth.
• Permanent teeth not erupting
• Bossing (bulging) of the forehead.
• Hypertelorism

Fibrous dysplasia

Fibrous dysplasia causes bone thinning^[4] and growths or lesions in one or more bones of the human body.

These lesions are tumor-like growths that consist of replacement of the medullary bone with fibrous tissue, causing the expansion and weakening of the areas of bone involved. Especially when involving the skull or facial bones, the lesions can cause externally visible deformities. The skull is often, but not necessarily, affected, and any other bone(s) can be involved.

Langer-Giedion syndrome

Langer-Giedion syndrome is a very rare genetic disorder caused by a deletion of chromosomal material. Diagnosis is usually made at birth or in early childhood.

The features associated with this condition include mild to moderate learning difficulties, short stature, unique facial features, small head and skeletal abnormalities including bony growths projecting from the surfaces of bones.

Maffucci syndrome

Maffucci syndrome is a sporadic disease characterized by the presence of multiple enchondromas associated with multiple simple or cavernous soft tissue hemangiomas. Also lymphangiomas may be apparent.

Patients are normal at birth and the syndrome manifests during childhood and puberty. The enchondromas affect the extremities and their distribution is asymmetrical.

Osteosclerosis

Osteosclerosis, an elevation in bone density,^[5] is normally detected on an X-ray as an area of whiteness, and is where the bone density has significantly increased. Localized osteosclerosis can be caused by injuries that compress the bone, by osteoarthritis, and osteoma.

Osteogenesis imperfecta

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.^[2] 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.

Other

• Deformity type Erlenmeyer flask gives a distal femur similar to an Erlenmeyer flask. It may result from Gaucher disease.^[6]
• Kashin–Beck disease
• Melnick–Needles syndrome
• Ovine chondrodysplasia

References