What is Osteogenesis Imperfecta?
OI iranian girl.jpg
10 year old Iranian girl with OI Type III. Permission acquired by publisher of article written by F.S Dijk et al. (6).


Osteogenesis Imperfecta (OI), also known as Brittle Bone Disease, is a genetic disorder resulting in fragility of bones. As a result, bone fractures and deformities are of higher risk in those patients with the disorder. There is a wide range of severity in those suffering from OI which may be lethal in the prenatal period, crippling postnatal or barely detectable which also result in varying life spans. Some types of OI may cause other complications such as respiratory distress,hearing loss, and muscle weakness 7. Phenotypic characteristics may result in blue sclerae, bowed legs, short stature and dentogenesis7. Initially, OI was classified as four main types (I-IV) all with varying characteristics and as of 2006, there are more than 8 genes, autosomal dominant and recessive, which have been identified to more than 8 types of OI1. The classification and severity of each case is dependent on the gene which is identified as well as phenotypic characteristics clinically and radiologically and is further discussed in the next page. In more than 90% of cases of OI, patients are classified as type I caused by a genetic mutation in the COL1A1 or COL1A2 gene which is involved in the synthesis of collagen fibers4. Both autosomal dominant and recessive mutations found can result in alterations through frameshifts, nonsense mutations and splicing which influence the affected pathways between cases. The remaining 6 genes which are responsible for multiple types of OI are autosomal recessive and affect different areas of the pathway which will be further explained.

My initial thought for this research was to find how OI may relate to other bone diseases such as osteoporosis, Brucks Syndrome or Paget's Bone Disease. Although there is debate that Bruck's Syndrome may be further considered as a type of OI7 ,further analysis of its causes is required. Due to the lack of findings between disorders, I continued to explore the genes which have been identified with Osteogenesis Imperfecta and proceeded with further analysis in relatedness to other species such as the house mouse, cattle, dogs, and monkeys. In understanding where these genes affect the synthesis of collagen, we may be able to use this research to identify different modes of gene therapy which may eventually lead to the correction of replenishing those genes which may be mutated, or to assist in the development of collagen to increase the bone density and decreasing the fragility and susceptibility to fractures in those suffering from OI.




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What is Osteogenesis Imperfecta?
Classification
The Genes Involved
Diagnosis and Treatment
References


Research by: Stacey St.HilaireUniversity of New Hampshire at ManchesterGenomics and Bioinformatics