Weissenbacher-Zweymüller syndrome ... (Weissenbacher-Zweymüller syndrome) - Gen COL11A2
Syndrome Weissenbacher-Zweymüller is a disorder that affects bone growth and is characterized by skeletal abnormalities, hearing loss and distinctive facial features. This disease has features that are similar to the otospondilomegaepifisalia dysplasia (OSMED) and Stickler syndrome type III. All of these entities are due to mutations in the same gene, and in some cases it may be difficult to distinguish. Sometimes it considered to represent a single disease with a range of signs and symptoms.
Newborns with Weissenbacher-Zweymüller syndrome are smaller than normal because the bones of the arms and legs are unusually short. The bones of the thighs and upper arms are shaped weights, and vertebrae can also be abnormally. Loss of hearing high pitched occurs in some cases. For its part, the distinctive facial features include bulging eyes, a small nose and directed upwards with a flat bridge, a small lower jaw and, in some cases, cleft palate.
This process is due to mutations in the gene COL11A2 (collagen type XI alpha 2), located on the short arm of chromosome 6 (6p21.3). This gene encodes a component of type XI collagen, called pro-alpha2 chain (XI). Type XI collagen adds structure and strength to the connective tissues of the body that support the muscles, joints, organs and skin. Type XI collagen is normally found in cartilage that makes up much of the skeleton in early development. Collagen type XI is also part of the vitreous, the inner ear and nucleus pulposus. Collagen type XI to form, pro-alpha2 chain (XI) is combined with two collagen chains, pro-alpha1 (XI) and pro-alpha1 (II) to form a procollagen molecule. These procollagen molecules are processed by enzymes in the cell. Once processed, the procollagen molecules out of the cell and arranged in long thin fibrils which are bonded together in the spaces around the cells. The crosslinks result in the formation of collagen fibers XI very strong mature type. XI collagen type also helps maintain separation and diameter of the fibrils of type II collagen. The type II collagen is an important component of the eye and mature cartilage tissue. The size and arrangement of collagen fibrils type II are essential for the normal structure of these tissues.
It has identified at least one mutation in the gene COL11A2 people with Weissenbacher-Zweymüller syndrome. This mutation replaces the amino acid glycine for glutamic acid amino acid at position 955 in pro-alpha2 chain (XI) (Gly955Glu). This mutation prevents the collagen molecules are assembled correctly, interrupting structure type XI collagen. These changes in type XI collagen result in signs and symptoms of Weissenbacher-Zweymüller syndrome, including short stature, distinctive facial features and sometimes hearing loss.
Syndrome Weissenbacher-Zweymüller is inherited as an autosomal dominant, which means that a copy of the altered gene in each cell is sufficient to express the disease. Most cases are due to new mutations in the gene that occur during the formation of reproductive cells or early embryonic development. These cases occur in people with no history of disease in your family.
Tests in IVAMI: in IVAMI perform detection of mutations associated with Weissenbacher-Zweymüller syndrome by complete PCR amplification of the exons of COL11A2 gene, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).