|Classification and external resources|
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.
- 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.
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.
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 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, an elevation in bone density, 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 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.
- Deformity type Erlenmeyer flask gives a distal femur similar to an Erlenmeyer flask. It may result from Gaucher disease.
- Kashin–Beck disease
- Melnick–Needles syndrome
- Ovine chondrodysplasia
- "Medcyclopaedia - Osteochondrodysplasia".[dead link]
- Geister, Krista A.; Camper, Sally A. (2015-01-01). "Advances in Skeletal Dysplasia Genetics". Annual Review of Genomics and Human Genetics. 16 (1): 199–227. doi:10.1146/annurev-genom-090314-045904. PMID 25939055.
- Wynn J, King TM, Gambello MJ, Waller DK, Hecht JT (2007). "Mortality in achondroplasia study: A 42-year follow-up". Am. J. Med. Genet. A. 143 (21): 2502–11. doi:10.1002/ajmg.a.31919. PMID 17879967.
- "fibrous dysplasia of bone" at Dorland's Medical Dictionary
- "Medcyclopaedia - Osteosclerosis". Retrieved 2007-12-23.
- Marks, Dawn B.; Swanson, Todd; Sandra I Kim; Marc Glucksman (2007). Biochemistry and molecular biology. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. ISBN 0-7817-8624-X.