The following information may help to address your question:
What is osteogenesis imperfecta?
(OI) is a group of genetic disorders that mainly affect the bones. People with this condition have bones that break easily, often from little or no trauma. Severity varies among affected people. Multiple fractures are common, and in severe cases, can even occur before birth. Milder cases may involve only a few fractures over a person's lifetime. People with OI also have dental problems (dentinogenesis imperfecta
) and hearing loss
in adulthood. Other features may include muscle weakness, loose joints, and skeletal malformations.
There are various recognized forms of OI which are distinguished by their features and genetic causes.
Depending on the genetic cause, OI may be inherited
in an autosomal dominant
(more commonly) or autosomal recessive
manner. Treatment is supportive and aims to decrease the number of fractures and disabilities.
Last updated: 10/6/2015
What causes osteogenesis imperfecta?
Osteogenesis imperfecta (OI) may be caused by changes (mutations
) in any of several genes
OI is most commonly due to a mutation in either the COL1A1
gene, causing OI types I through IV. These genes play a role in how the body makes collagen, a material that helps to strengthen the bones. The type and severity of OI depends on the effect that the specific mutation has on normal collagen production.
OI caused by mutations in these genes is inherited in an autosomal dominant
manner. In about 10% of people with OI, the COL1A1
genes are normal and the condition is due to mutations in other genes; many of these people have an autosomal recessive
form of OI.
Other genes in which mutations may be responsible for less common types of OI, some of which have been reported in only one individual or family, include:
LEPRE1, also called P3H1
Last updated: 10/7/2015
How is osteogenesis imperfecta inherited?
Osteogenesis imperfecta (OI) is most commonly inherited in an autosomal dominant
manner. This means that having only one changed (mutated
) copy of the responsible gene in each cell
is enough to cause features of OI. The mutated copy of the gene may be inherited from an affected parent, or it may occur for the first time in an affected person (a de novo
mutation). When a person with an autosomal dominant form of OI has children, each child has a 50% (1 in 2) chance of inheriting the mutated gene
If the child inherits the mutated gene, the child's symptoms may be milder, or more severe, than those of the parent.
Less commonly, OI is inherited in an autosomal recessive
manner. This means that both copies of the responsible gene in each cell must have a mutation for a person to be affected. The parents of a person with an autosomal recessive condition typically are unaffected, but each carry one mutated copy of the gene. When two carriers
of an autosomal recessive form of OI have children, each child has a 25% (1 in 4) chance to be affected, a 50% (1 in 2) chance to be a carrier like each parent, and a 25% chance to be unaffected and
not be a carrier.
Last updated: 10/9/2015
Can childbirth be done naturally or will a C-section need to be performed?
In general, decisions about the best mode of delivery (vaginal vs. cesarean) should be made on an individual basis and may include discussion with the hospital’s neonatologist
, chief obstetrical nurse, and nursery staff. Currently, there is no research data showing that one mode of delivery is safer than the other in women with osteogenesis imperfecta (OI) who have normal pelvic
dimensions and no other significant complications.
A study from 2001 showed that infants with non-lethal forms of OI did not
have lower fracture rates with a cesarean delivery compared to a vaginal delivery. A cesarean delivery was also not
found to prolong survival for those with more severe forms of OI.
A more recent study in 2015 also concluded that cesarean delivery did not
decrease fracture rate at birth. This study further stated that cesarean delivery is only necessary if there are other maternal or fetal indications, not just for the purpose of preventing fractures at birth.
Another 2015 study indicated that vaginal delivery did not
cause an increase in pregnancy complications for women with OI.
Additional information regarding OI and pregnancy can be found through the Osteogenesis Imperfecta Foundation by clicking here
Last updated: 12/7/2015
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