Fibrous dysplasia
Encyclopedia
Fibrous dysplasia is a disease
that causes bone thinning and growths or lesion
s in one or more bones, and leads to bone weakness and scar formation within the bones.
-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.
In 3% of cases, people suffering from fibrous dysplasia also have endocrine diseases and skin pigmentation; the three together constitute McCune-Albright syndrome
. These endocrine diseases include precocious (early) puberty, often occurring as early as 6 years old.
C-fos
are raised in fibrous dysplasia, leading to gene over-expression and tumour formation.
It is not hereditary.
There are two types of fibrous dysplasia:
The most severe form of polyostotic fibrous dysplasia is known as McCune-Albright syndrome
.
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
that causes bone thinning and growths or lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
s in one or more bones, and leads to bone weakness and scar formation within the bones.
Presentation
These lesions are tumorTumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
-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.
- Many patients have lesions localized in only one bone (monostotic fibrous dysplasiaMonostotic fibrous dysplasiaMonostotic fibrous dysplasia is a form of fibrous dysplasia where only one bone is involved. It comprises a majority of the cases of fibrous dysplasia.It is also known as "Jaffe-Lichtenstein syndrome"....
), affecting 70-80%. - Others have them in many bones (polyostotic fibrous dysplasiaPolyostotic fibrous dysplasiaPolyostotic fibrous dysplasia is a form of fibrous dysplasia affecting more than one bone.The McCune-Albright syndrome includes polyostotic fibrous dysplasia as part of its presentation....
).
In 3% of cases, people suffering from fibrous dysplasia also have endocrine diseases and skin pigmentation; the three together constitute McCune-Albright syndrome
McCune-Albright syndrome
McCune–Albright syndrome, described in 1937 by Donovan James McCune and Fuller Albright, is a genetic disorder of bones, skin pigmentation and hormonal problems along with premature puberty.-Symptoms:...
. These endocrine diseases include precocious (early) puberty, often occurring as early as 6 years old.
Causes
Fibrous dysplasia is very rare; not much is known about it, and there is no known cure. Levels of the transcription factorTranscription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...
C-fos
C-Fos
In the field of molecular biology and Genetics, c-Fos is a protein encoded by the FOS gene.-Structure and function:c-Fos is a cellular proto-oncogene belonging to the immediate early gene family of transcription factors. c-Fos has a leucine-zipper DNA binding domain, and a transactivation domain at...
are raised in fibrous dysplasia, leading to gene over-expression and tumour formation.
It is not hereditary.
There are two types of fibrous dysplasia:
- Monostotic (Involving a single bone, or adjecent bones, like both the upper and lower jaw)
- Polyostotic (Involving many bones).
The most severe form of polyostotic fibrous dysplasia is known as McCune-Albright syndrome
McCune-Albright syndrome
McCune–Albright syndrome, described in 1937 by Donovan James McCune and Fuller Albright, is a genetic disorder of bones, skin pigmentation and hormonal problems along with premature puberty.-Symptoms:...
.
External links
- Fibrous Dysplasia Pictures MedPix Imaging Database
- Fibrous Dysplasia of the Skull Images radRounds Radiology Image Database
- Fibrous Dysplasia Foundation