Platispondílica lethal skeletal dysplasia, Torrance (Platyspondylic dysplasia lethal skeletal, Torrance type) type - COL2A1 gene.
Platispondílica lethal skeletal dysplasia Torrance type is a serious disturbance of bone growth, characterized by very short arms and legs, underdeveloped pelvic bones, brachydactyly, platyspondyly and lordosis. Children with this disorder are born with a small Torx with short ribs which can restrict growth and lung expansion. As a result of these serious health problems, some affected fetuses do not come to term. In general, affected infants die at birth or shortly after birth from respiratory failure. Some people affected with milder signs and symptoms have lived to adulthood.
This disease is due to mutations in the COL2A1 gene, located on the long arm of chromosome 12 (12q13.11). This gene encodes a component of collagen type II, called the pro-alpha1 (II) chain. This type of collagen is found primarily in the vitreous and cartilage. Most cartilage is later converted to bone. Collagen type II is essential for normal bone development and other connective tissues that form the support frame body. Collagen type II is also part of the vitreous, the inner ear and nucleus pulposus.
There are more than 10 mutations in the COL2A1 gene in people with lethal skeletal dysplasia type platispondílica Torrance. All associated mutations occur in a region of the pro-alpha1 (II) chain called C-propeptide domain. Often, mutations change a single amino acid in the pro-alpha1 (II) chain. Mutations in the COL2A1 gene encoding result of an abnormal version of the pro-alpha1 (II) chain can not be incorporated into the fibers of type II collagen. As a result, a reduced amount of type II collagen occurs. Instead of forming collagen molecules, pro-alpha1 (II) chains abnormal accumulate in chondrocytes. These changes alter the normal development of bones, which lead to skeletal abnormalities characteristic of lethal skeletal dysplasia type platispondílica Torrance.
This disease is inherited as an autosomal dominant, which means that a copy of the altered gene in each cell is sufficient to express the disease. In some cases, an affected person inherits the mutation from an affected parent. Other cases are due to new mutations in the gene and occur in people with no history of disease in your family.
Tests in IVAMI: in IVAMI perform detection of mutations associated with lethal skeletal dysplasia type platispondílica Torrance, by complete PCR amplification of exons COL2A1 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).