How does OI affect collagen?
Osteogenesis imperfecta, also known as brittle bone disease, is a genetic disorder that causes bones to break easily without cause. The condition affects the body’s ability to produce collagen, a protein in the body’s connective tissue.
Why is OI type 2 lethal?
Generally, there is a correlation between the clinical features and genetic mutation. OI type II is the most severe form. It is a lethal form with collagen abnormalities resulting in dwarfism, bone fragility and deformity with in utero or perinatal death [2].
Is OI type II dominant or recessive?
Most types of OI are inherited in an autosomal dominant pattern. Almost all infants with the severe type II OI are born into families without a family history of the condition. Usually, the cause in these families is a new mutation in the egg or sperm or very early embryo in the COL1A1 or COL1A2 gene.
What protein is defective in osteogenesis imperfecta?
The current OI paradigm is that of a collagen-related bone dysplasia, with most dominant cases caused by defects in type I collagen itself, while rare recessive forms are caused by defects in genes whose products interact with collagen (1, 2).
What type of collagen is defective in osteogenesis imperfecta?
The mutations that cause osteogenesis imperfecta types II, III, and IV occur in either the COL1A1 or COL1A2 gene. These mutations typically alter the structure of type I collagen molecules, resulting in abnormal type I collagen.
What chromosome is affected in osteogenesis imperfecta?
Osteogenesis imperfecta type XIX is inherited in an X-linked recessive pattern . A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell.
What is the pathogenesis of osteogenesis imperfecta?
The most common form of OI is caused by mutations in the two collagen type I genes. Stop mutations usually lead to reduced collagen amount resulting in a mild phenotype, while missense mutations mainly provoke structural alterations in the collagen protein and entail a more severe phenotype.
Why is sclera blue in osteogenesis imperfecta?
Blue sclera is the most commonly known ocular sign for osteogenesis imperfecta and it is caused by thin scleral collagen allowing the underlying darker choroid vasculature to be seen. Patients with OI have shown a reduction in thickness of the corneal and scleral collagen fibers which can result in low ocular rigidity.
How does osteogenesis occur?
There are two major modes of bone formation, or osteogenesis, and both involve the transformation of a preexisting mesenchymal tissue into bone tissue. The direct conversion of mesenchymal tissue into bone is called intramembranous ossification. This process occurs primarily in the bones of the skull.
What is the caused of osteogenesis imperfecta and how is the bone affected?
Osteogenesis imperfecta (OI) is a genetic disorder of connective tissues caused by an abnormality in the synthesis or processing of type I collagen. It is also called brittle bone disease. It is characterized by an increased susceptibility to bone fractures and decreased bone density.
Is Salmonella pathogenicity island 2-encoded type III secretion system?
Gallois, A., J. Klein, L. Allen, B. Jones, and W. Nauseef.2001. Salmonella pathogenicity island 2-encoded type III secretion system mediates exclusion of NADPH oxidase assembly from the phagosomal membrane. J.
Is Vibrio cholerae a type III secretion system?
Genomic characterization of non-O1, non-O139 Vibrio cholerae reveals genes for a type III secretion system. Proc. Natl. Acad. Sci.
What is a small-molecule inhibitor of Type III secretion of Chlamydia trachomatis?
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