Osteogenesis Imperfecta

By: Rabab Jafri

What Causes OI?

The dominant mutations happen on the gene COL1A1 or COL1A2 gene

Recessive mutation occur on (CRTAP) gene or the LEPRE1 gene

Mutation on chromosome 17 OI is caused by an abnormal

production of collagen. Collagen structural protein material

for bones, skin, cartilage, and ligaments.

Chromosome 17

Types of OI

OI was thought to have been dominant autosomal, but research has found types of recessive OI as well.

Type I This is the most common form of OI It’s dominant autosomal Least severe Have normal or near-normal height Loose joints, weak muscles Whites of highs have blue, purple, or gray

tint Some or no bone deformity Possible curved spine Possible hearing loss Normal collagen, less than normal amount

Type II Most severe Most people with this type

die soon after birth Many times fatalities caused

by deformed lungs Many fractures, severe bone

deformity Small stature Whites of eyes tinted Collagen not formed

properly Dominant autosomal

Type III Easily fractured bones, some occurring before

birth, some healed before birth Short stature Whites of eyes tinted Loose joints and muscle development poor in

limbs Curved spine Possible respiratory problems severe deformed bones Brittle teeth and hearing loss possible Collagen not formed properly Dominant Autosomal

Type IV Less severe than type III Fragile bones, fracture often Below average stature Eye whites have little or no tint Some bone deformity, not severe Tendency toward curved spine Ribs are barrel-shaped Could have brittle teeth and weak

hearing Collagen not formed properly Dominant autosomal

Type V Similar to IV in symptoms and

clinically Large calluses Forearm rotation restricted Whites of eyes normal Normal teeth Dominant pattern This type is caused by unidentified

mutations Don’t have mutations in type I

collagen genes

Type VI

Similar to type IV in symptoms and clinically

Activity of alkaline phosphatase is elevated

Unknown whether it’s dominant or recessive, but most likely recessive

By 2007, only 8 people had been diagnosed with this type of OI

Type VII

Could be like type IV Could be like type II, but with normal eye whites Below average stature Short arm bone Short upper leg bone Coxa vera is possible Recessive autosomal Caused by CRTAP gene

Type VIII

could be like type II Could be like type III Normal whites of eyes Growth deficiency is very severe Deficiency of PH31 Recessive autosomal Caused by LEPRE1 gene

Treatment

There is no known cure for OI There are treatments to help

symptoms of OI Making sure bones are as healthy as

possible is important Surgical and dental procedures as

well as physical therapy may be recommended

“Rodding Surgery” which is done by putting metal rods next to long bones to strengthen them and prevent deformity

Impact on people with OI

Since severity differs most live life normally, and others have problems

Some have deformity of limbs and other parts of the body which could make mobility limited

Some just have fragile bones Some have tinted eyes Some have hearing problems or are deaf Some don’t live long after their born (type II) Most of them live happy successful lives like anyone else

Research Outlook

Many different types of research are being done although researchers seem like they’re looking for different treatments rather than cures right now

The research includes looking at the affects of vibration therapy, Tariperatide (in adults), Bisphosphonates, and other treatments.

There is hope for a cure, but not soon, right now treatments are the main focus

Myth Busters (AKA two extra interesting facts! :D)

Myth: Babies with OI should be carried around with a pillow and discouraged from moving.

Truth: It’s good to take precautions, but it makes it so the baby doesn’t discover movement naturally. Also immobility leads to loss in bone mass which would cause more problems

Myth Busters (continued)

Myth: If a parent has OI, so will their child

Truth: It could either be a dominant or recessive trait. If one parent has dominant OI, there is a 50% chance their child will get it. If it’s recessive, the child has a 25% chance they’ll be affected and a 50% chance of being a carrier

Recommended websites

Oif.org Emedicine.medscape.com

Organizations

OI Foundation Medical Research Charities Charity Navigator National Health Council

Work Cited

OI :: Osteogenesis Imperfecta :: A Rare Genetic Disorder :: Brittle Bone

Disease. Web. 18 Apr. 2011.<http://www.easilybrokenbones.com/>.

"Osteogenesis Imperfecta - Genetics Home Reference." Genetics Home Reference - Your Guide to

Understanding Genetic Conditions. 14 Apr. 2011. Web. 18 Apr. 2011.

<http://ghr.nlm.nih.gov/condition/osteogenesis-imperfecta>.

"Osteogenesis Imperfecta: MedlinePlus." National Library of Medicine - National Institutes of

Health. 11 Jan. 2011. Web. 18 Apr. 2011.

<http://www.nlm.nih.gov/medlineplus/osteogenesisimperfecta.html>.

"Typed of OI." Osteogenesis Imperfecta Foundation:. 2007. Web. 18 Apr. 2011.

<http://www.oif.org/site/PageServer?pagename=AOI_Types>.