Hipocondrogénesis (Hypochondrogenesis) - COL2A1 gene.

The hipocondrogénesis is a severe and rare bone growth disorder, characterized by a small body, a few short limbs and abnormal ossification in the spine and pelvis. Affected children have arms and short legs, a small chest and underdeveloped lungs. The bones in the skull develop normally, but the vertebrae and pelvis not ossify properly. Other additional signs and symptoms include flat, oval - shaped face, widely spaced eyes, a small chin, cleft palate, enlarged abdomen and hydrops fetalis. As a result of these serious health problems, some fetuses do not survive. Generally, infants die or shortly after birth from respiratory failure. It is considered that newborns who live beyond the neonatal period have hipocondrogénesis but spondyloepiphyseal developmental dysplasia, a related but milder disorder that affects bone development similarly.

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 the nucleus pulposus.

They have identified at least 18 mutations in the COL2A1 gene in people with hipocondrogénesis. Some mutations of the COL2A1 gene deleted or result chains pro-alpha1 (II) in the missing critical segments. Other mutations replace the amino acid with a different amino acid glycine at various locations of the collagen chain. All these mutations interfere with the formation of molecules of type II collagen, which results in characteristics of the disease because affects tissues that are rich in type II collagen.

This disease is considered to have a pattern of autosomal dominant because a copy of the altered gene in each cell is sufficient to cause the alteration. It is caused by mutations in the COL2A1 new gene and occurs in people with no history of disease in your family. This disease to the next generation is not transmitted, because affected individuals do not live long enough to have children.

Tests in IVAMI: in IVAMI perform detection of mutations associated with hipocondrogénesis, 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).