This web page was produced as an assignment for Genetics 677, an undergraduate course at UW-Madison.
What is
Osteogenesis Imperfecta?
Osteogenesis
imperfecta (OI) is the name given to a group of bone disorders that cause the
affected individuals to become much more susceptible to bone fractures. These individuals can also display
dental problems due to improper teeth formation and progressive hearing loss as
they age. There is a wide spectrum
of symptom severity; some patients will die prior to birth, while others may
display few obvious physical abnormalities other than an increased risk of bone
fracture. [1]
Prevalence of
OI
Approximately 6
or 7 individuals out of every 100,000 are afflicted with one of the several
types of osteogenesis imperfecta (OI).
All people can be afflicted regardless of race. However, approximately 90% of the
individuals diagnosed with OI types I, II, III, or IV will have a mutation
present in either COL1A1 or
COL1A2. [1]
Is there
hope?
The wide
spectrum of symptoms indicates that it is unlikely that just one gene
responsible for causing OI.
However, many individuals afflicted with one of these disorders display
mutations in the same genes. These
results lend hope to families and researchers that better treatments can be
developed. These identified
mutations also allow families to utilize genetic counseling if they so choose.
What are COL1A1
and COL1A2?
COL1A1 and COL1A2 refer to the two collagen genes. Collagen is utilized throughout the
human body to strengthen and support many crucial structures, including
bones. [2]
Mutations in COL1A1 can lead to other connective tissue disorders,
however OI is the most common.
Several hundred mutations within this gene have been identified and
correlated with patients expressing OI.
It is believed that these mutations directly cause the phenotypes found
in patients diagnosed with OI. [2]
So what?
Specifically, I
will be focusing on COL1A1
and its relation to the incidence of OI in human individuals. This gene is specifically called
“collagen, type one, alpha one” and it is responsible for directing the
creation of one part of Type I collagen molecules [2]. Throughout the rest of this semester,
it is my hope to learn about osteogenesis imperfecta and where future research
into genetic mutations may lead.
Above is Atticus Shaffer, a 12-year-old actor currently starring in ABC's comedy 'The Middle.' He has been diagnosed with osteogenesis imperfecta [3]. Image Credit: ABC Media Net
References
1. “Osteogenesis
Imperfecta: Brittle Bone Disease, OI." Review. Gene Reviews 28 Jan. 2005.National Center for
Biotechnology Information. Web. 07 Feb. 2011.
<http://www.ncbi.nlm.nih.gov/books/NBK1295/>. 2. "COL1A1." Genetics Home Reference. U.S. National Library of Medicine, 06 Feb. 2011. Web. <http://ghr.nlm.nih.gov/gene/COL1A1>. 3.
Barnes, Brooks. "Everybody Loves the Weird Kid." The New
York Times 06 May 2010. Print.