Imperfect Osteogenesis

The imperfect osteogenesis (of Latin Osteogenesis imperfecta ) is a group of diseases characterized by an excessive osseous brittleness, which had with a congenital defect of development of the fibers Collagène S of the conjunctive Tissu which forms the screen of the Os, of the anomalies of the Dentition and often a hearing impairment.

The clinical demonstrations of this disease are very varied active from a simple coloring blue of the Sclérotique until a lethal form with the birth while passing by severe forms involving a major handicap at the person reached.

Historically classified in four types according to clinical description, there exist now seven types and future knowledge will probably find others of them.

In France, 2 000 people suffer from this disease, which is characterized by an extreme brittleness of the bones. Fractures with repetition, beginning as of the birth, mark out the existence of the patients. Cause this brittleness: a competition between cells. In a healthy bone, there exists a dynamic balance between the Ostéoclaste S (or myéloplaxe ), cells charged to destroy bone tissue, and the Ostéoblaste S, charged to reform new. What is destroyed of an east coast rebuilt of the other. In the case of an imperfect osteogenesis, the osteoclasts “take the top”: fractures and deformations of the members and the skeleton appear. At certain people the teeth are not saved: they become translucent and fragile. Disorders of hearing (Otospongiose) are also possible. And most of the time, the person reached is of very small size. A life constantly enamelled of hospitalizations and rehabilitation.

The same one from which Michel Petrucciani suffered, the pianist of jazz, and the character interpreted by Samuel Jackson in the film Incassable of Mr. Night Shyamalan.

Other terms of the disease

In fat the terms most employed but the term imperfect osteogenesis should be only the utilisé

Maladie of the blue eyes;
Disease of OS of Glass ;
congenital osseous Brittleness (1959);
hereditary osseous Brittleness (1959);
Men of glass (1928);
Triad of van der Hoeve (1918);
Dysplasie périostale of Lasting (1905);
Porak Disease and Lasting (1894);
Pseudorachitismus (1891);
Disease of Vrölik (1849);
Osteogenesis imperfecta (1849);
Disease of Lobstein (1833);
Ostéopsathyrose idiopathic (1829);
Rachitis congenita (1822);

Gene in question

It is the change of the COL1A1 of the chromosome 17 or COLLAR 1A2 of the chromosome 7. These genes code the chains alpha 1 and alpha 2 of the collagen of the type I

Incidence

Incidence 1 per 5000 births

Clinical demonstrations

Old classification

Type 1

more frequent
Sclerotic blue
Hearing impairment in 50% of the cases
Little fracture and deformation limits
Dominating autosomic

Type 2

autosomic dominant autosomic Transmission by change of novo
lethal Form (mortal)
Sclerotic blue
Fracture of dimension responsible for the death by respiratory insufficiency very quickly after the birth

Type 3

dominant or recessive Transmission autosomic
the nonlethal most severe form
triangular Face
Sclerotic blue
important Fractures with deformation and reduction of size

Type 4

Very mixed group gathering the cases not classified in the first three cases
autosomic dominant Transmission
Sclerotic white

New classification

Diagnosis

Anténatal

Only types II and III are diagnosable échographiquement in anténatal.

Postnatal

The clinical criteria of diagnosis are:

Fracture of the bones for a tiny traumatism; These fractures often reach the end of the bone
Small size with deformed bones or cuts smaller than the other family members
Sclérotique blue
Trouble of teeth
Surdité often appearing after adolescence

The radiographic aspects of the bone contribute to the diagnosis.

Differential

Syndrome of Bruck
Syndrome of Adhesive-Carpenter
Syndrome of Hadju-Cheney
Syndrome osteodysplastic osteoporosis pseudogliome
Gérodermie
idiopathic youthful Osteoporosis

Pregnancy at a woman carrying an imperfect osteogenesis of Type 1

Risk of uterine rupture during a childbirth by low way
Increase in the risk of hemorrhage of the delivery
Increase in the malignant risk of hyperthermia during a general anesthesia

Others

Michel Petrucciani, musician of Jazz, was carrying this disease
In the film the fabulous destiny of Amélie Poulain, Serge Merlin plays the part of Raymond Dufayel, the man of glass: " Because of a congenital disease, its bones break like crystal. A simple handshake being likely to crush the metacarpus to him, that made twenty years that it avoids leaving at his place. It spends its time reproducing the " to lunch of the canotiers" of Renoir, at a rate of one per annum, since twenty ans."

Sources

Impossible to circumvent for the genetic diseases
Robert D Steiner, Melanie G Pip, Peter H Byers, Osteogenesis Imperfecta in GeneTests: Medical Genetics Information Resource (database online). Copyright, University off Washington, Seattle. 1993-2006

External bonds

Association of Imperfect Osteogenesis (France);
Belgian French-speaking Association of Imperfect Osteogenesis;
Swiss Association Osteogenesis Imperfecta (French/German);
OI Foundation (English);
OIFE (Europe) (various).

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