Comprises a heterogeneous group of heritable
disorders characterized by impairment of
It arises due to mutations in one of two genes
that guide the formation of type 1 collagen : COL
1 A1 gene on chromosome 17 and COL 1 A2
gene on chromosome 7.
Collagen forms a major portion of bone,
dentin,sclerae,ligaments and skin; osteogenesis
imperfecta demonstrate a variety of changes
that involve these sites.
Extreme fragility and porosity of the bones, with
proneness to fracture.
Some affected individuals also have blue sclera
, altered teeth , hypoacusis , long bone and
spine deformities , and joint hyperextensibility.
Many patients also have a tendency towards
Opalescent dentin in patient with
Based on Sillence et al classification, 4 types of
osteogenesis imperfecta exist –
1. TYPE 1 Osteogenesis imperfecta
2. TYPE 2 Osteogenesis imperfecta
3. TYPE 3 Osteogenesis imperfecta
4. TYPE 4 Osteogenesis imperfecta
TYPE 1 OSTEOGENESIS
Most common and mildest form.
Symptoms include blue sclera , in utero
fractures in 10 % of patients , mild to moderate
bone fragility with frequency of fractures
decreasing after puberty , hearing loss , easy
bruising and short stature.
It is an autosomal dominant trait.
TYPE 2 OSTEOGENESIS
Most severe form.
Exhibits extreme bone fragility and frequent
In utero fractures are present in 100% of cases.
Blue sclera may be present , hearing loss is not
Small nose, micrognathia and short trunk may
Both autosomal recessive and dominant
patterns may occur.
TYPE 3 OSTEOGENESIS
Most severe form noted in individuals beyond
the prenatal period.
Sclera of variable hue , limb shortening and
progressive deformities and pulmonary
In utero fractures occur in 50% of cases.
No hearing loss reported in this type.
Both autosomal recessive and dominant
patterns may occur.
TYPE 4 OSTEOGENESIS
Associated with mild to moderately severe bone
Symptoms include normal sclera, normal
hearing, fractures that begin in infancy and mild
angulation and shortening of long bones.
The frequency of fractures decreases with
This variant is an autosomal dominant trait.
The radiographic hallmarks of osteogenesis
imperfecta include osteopenia, bowing,
angulation or deformity of the long bones,
multiple fractures and wormian bones ( sutural
bones ) in the skull.
Radiograph typically reveal premature pulpal
obliteration , although shell teeth rarely may be
The bone cortex is thin and porous. The bone
trabeculae are thin delicate and widely
Osteoblastic activity appears retarded and
imperfect and for this reason the thickness of
long bone is deficient.
Failure of woven bone to become transformed
to lamellar bone.
Defective microvascular system and decreased
collagen fibril diameter have been observed.
There is no cure for OI, thus symptomatic
improvement is the primary goal of currently
available treatment options.
The mainstays of treatment are
PHYSIOTHERAPY, REHABILITATION and
The prognosis varies from relatively good to
Also known as – MARBLE BONE DISEASE ,
ALBERS-SCHONBERG DISEASE ,
It is a rare hereditary bone disease of
heterogeneous pathophysiology in which failure
of osteoclastic bone resorption leads to
increased bone mass.
A German radiologist, Albers- schonberg, first
described osteoporosis in 1904.
The primary underlying defect is failure of the
osteoclasts to resorb bone.
Defective osteoclastic bone resorption ,
combined with continued bone formation and
endochondral ossification , results in thickening
of cortical bone and sclerosis of the cancellous
Heterogeneous molecular or genetic defects
can result in impaired osteoclastic function.
Three distinct forms of the disease are based on
age and clinical features – ADULT ONSET,
INFANTILE , and INTERMEDIATE.
The infantile and intermediate types have an
autosomal recessive mode of transmission,
while adult onset type shows autosomal
If untreated, infantile type results in death by
first decade of life.
Adult onset type are asymptomatic and have
good long term survival rates.
Also called MALIGNANT OSTEOPOROSIS.
Diagnosed early in life.
Failure to survive and growth retardation are
Bony defects occur
Nasal stuffiness due to mastoid and paranasal
sinus malformation is often the presenting
Cranial nerve entrapment neuropathies occur.
Manifestations include deafness, proptosis and
Dentition might be delayed.
Bones are fragile and can fracture easily,
osteomyelitis of mandible is common due to
deficient blood supply.
Patients might have anemia, easy bruising,
bleeding, recurrent infections,
hemolysis, sleep apnea and blindness.
Also called BENIGN OSTEOPOROSIS.
Diagnosed in late adolescence or adulthood.
Approximately one half of the patients are
asymptomatic and diagnosis is made
incidentally or is based on family history.
Other patients might present with osteomyelitis
Many patients have bone pain.
Bones are fragile and might fracture easily.
Bony defects are common and include cranial
nerve entrapment neuropathies and
40% of patients have recurrent fractures while
osteomyelitis of mandible occur in 10% of
Other manifestations include visual entrapment,
hepatospleenomegaly, short stature, large head
Patients usually have generalized
The bones might appear club like or show an
appearance of a bone within bone.
Vertebrae are extremely radiodense. They may
show alternating bands, known as the Rugger –
The entire skull is thickened and dense ,
especially at the base.
The roots of the teeth often are difficult to
visualize because of the density of the
Several patterns of abnormal endosteal bone
formation have been described.These include
the following –
Tortuous lamellar trabeculae replacing the
cancellous portion of bone.
Globular amorphous bone deposition in the
Osteophytic bone formation.
Numerous osteoclasts may be seen, but there is
no evidence that they function.
Calcitriol appears to help by stimulating dormant
osteoclasts and thus stimulating bone
Erythropoietin can be used to correct anemia.
Corticosteroids have been used with the hope of
stimulating bone resorption and treating the
Treatment with gamma interferon has been
shown to produce long term benefits.
No specific medical treatment exists for the