Osteogenesis imperfecta is a genetic disorder characterized by fragile bones that fracture easily. It results from a defect in type I collagen production, the main protein in bone matrix, which leads to low bone mass and increased bone fragility. The condition ranges from mild to lethal. Types are classified based on severity and inheritance. Diagnosis involves examining for blue sclera and bone fractures or deformities on imaging. Treatment focuses on physiotherapy, orthopedic surgery, and bisphosphonates to increase bone strength. Differential diagnoses include child abuse and juvenile osteoporosis.

1. Osteogenesis imperfecta
PRESENTED BY
Dr. Mahesh Chaudhary
MD (RESIDENT) PHASE-B
RADIOLOGY & IMAGING DEPARTMENT
BSMMU, DHAKA
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2. Osteogenesis imperfecta
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It is genetically heterogeneous group of collagen
disorders.
It is also known as brittle bones disease/
fragilitas ossium.
It results from a defect of type I collagen
production (major protein of bone matrix) that
leads to congenital osteopenia with increased
bone fragility, low bone mass, and other
connective tissue manifestations like dental
abnormalities, lax joints, thin skin.
It is a heritable condition of connective tissue.

3. Osteogenesis imperfecta
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It occurs in 1:20,000 to 1:60,000 of live births.
It occurs with equal frequency among males and
females and across races and ethnic groups.
The hallmark feature of OI is fragile bones that
fracture easily.
Classical clinical triad of OI is fragility of bone, blue
sclera, and deafness (due to ankylosis of ossicles &
osteosclerosis) .
OI affects both bone quality and bone mass.
In some people, height, hearing, skin, blood vessels,
muscles, tendons, and teeth may also be affected.

4. Osteogenesis imperfecta
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It is probably the most common form of skeletal
dysplasia requiring substantial orthopaedic care.
Although the disease is usually apparent at birth or in
childhood, more mild forms of the disease may not
become apparent until adulthood, when affected
individuals may present with insufficiency fractures and
osteopenia.
In the more severely affected fetuses antenatal
diagnosis may often be made in the second trimester
on the basis of shortened long bones with multiple
fractures.
The thorax tends to be short but not narrow.

5. Osteogenesis imperfecta
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Pathophysiology
In most cases, OI is caused by a dominant mutation in
the COL1A1 or the COL1A2 genes that encode type I
collagen.
Fewer than 10 percent of OI cases are believed to be
caused by recessive mutations in other genes in the
collagen pathway.
Here is the production of abnormal collagen I
molecules as well as a decrease in the production of
normal collagen I molecules. This results from
mutations in the loci coding for pro-α 1 and pro-α 2
chains which form the helical structure of collagen 1.

6. Radiographic features
Radiographic features vary according to the type
of disease and its severity and include
osteopenia and fractures, which may heal with
florid callus formation, mimicking
osteosarcoma.
Bones are thin and under-tubulated (gracile),
normal in length or shortened, thickened and
deformed by multiple fractures.
Intra-sutural (Wormian) bones can be identified
on skull radiographs.
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7. Radiographic features
In severe forms of osteogenesis imperfecta the
diagnosis may be made before birth by
detailed ultrasound in the second trimester.
Diagnostic features include cranial
enlargement, reduced echogenicity of bone
and deformity and shortening of limb bones
as a result of intrauterine fractures.
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8. Classification of Osteogenesis imperfecta
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The classification of osteogenesis imperfecta is
that devised by Sillence et al in 1979 and modified
in 1986.
The important characteristics in this classification
include
blue sclera
severity of the disorder &
the mode of inheritance (dominant, recessive,
sporadic/new mutation)
However accurate classification is difficult
because of phenotypic overlap.

9. Osteogenesis Imperfecta
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Two forms:
Congenita-Life expectancy short.
Tarda-Life expectancy is normal
Types: 4 types
Osteogenesis Imperfecta Type I
Osteogenesis Imperfecta Type II
Osteogenesis Imperfecta Type III
Osteogenesis Imperfecta Type IV

10. Osteogenesis Imperfecta-Type I
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A mild form of this condition (occurs in 70% cases).
It has autosomal dominance inheritance.
Sclera becomes blue.
Bone fragility mild.
Fracture rates in childhood diminish with increasing
skeletal maturity only to increase again in middle life,
particularly in postmenopausal women
Stature is normal or only mildly reduced.
Deafness occurs in adult life.
People suffering from it can expect to live as long as
any normal individual.

11. Osteogenesis Imperfecta- Type I
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Subdivision:
 Group A: No dental involvement but presence of
minor skeletal changes.
 Group B: Subjects with dentinogenesis imperfecta &
more severe skeletal changes.
Osteoporosis occurs with cortical thinning with
bowed thin gracile long bones.
In 10% fractures are seen at birth.
Most fracture occurs in young children.
Wormian bones are seen in skull.

15. Osteogenesis Imperfecta Type II
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It is generally estimated to be the most severe type of
OI.
Individuals with Osteogenesis Imperfecta Type 2
generally die within the first year of their life.
Sclera are blue.
Overall bones are grossly demineralised with thin
cortices.
Numerous healing or healed fractures are seen at
birth despite protection of amniotic fluid. Fractures
are occurs during delivery.

16. Osteogenesis Imperfecta Type II
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Sub types:
Type 2A: The long bones are bowed, short and broad.
Numerous fractures are seen. The ribs are broad with
continuous beading.
Type 2B: The long bones are as in Type 2A, but the ribs
show no beading or less beading.
Type 2C: The long bones are thinned, shows numerous
fractures and the ribs too are thin & beaded.

17. Osteogenesis imperfecta.
Osteogenesis
imperfecta.
The child is stillborn.
Multiple fractures are
demonstrated in the
short and broad long
bones, which are cystic
in appearance.
Numerous rib fractures
are seen.

18. Osteogenesis imperfecta congenita (type II)

19. OI type II in a fetus.
There are fractures in all
the long bones.
Multiple fractures are
present in the ribs,
leading to shortened ribs
with a characteristically
“ beaded ” appearance.
Also there is poor
ossification of the skull

21. Osteogenesis Imperfecta- Type III
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This occurs in 15% of the patients, is a severe and
progressively deforming type & is usually due to new
mutation.
Affected individuals suffer from multiple fractures that
start from the initial years of their life result in bowing.
Overall bones are demineralised. Vertebral compression
is seen and a kyphoscoliosis results. The long bones are
osteoporotic and thin.
Sclera may be blue at birth but are usually normal in
adolescence.
In skull ossification is poor, sutures are wide and
wormian bones persists.
It also has association with dentinogenesis imperfecta.

24. Osteogenesis Imperfecta- Type IV
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It is a mildly severe form of this disorder and is
similar to Type I. However, Osteogenesis Imperfecta
Type 4 sufferers need crutches and braces to walk.
Life expectancy is close to normal or completely
normal.
This types constitutes 5%.
Sclera-normal.
Fractures are seen at birth 30% and bony fragility is
mild.
Subtypes: 2
4A with no dental lesion
4B with dentinogenesis imperfecta

26. Osteogenesis Imperfecta and Eyes
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The reduced functioning of Type I collagen leads to
the thinning of the sclera and consequent showing
of the underlying veins through the whites of eyes.
Blue Sclera is one of the major symptoms of OI and
helps in the diagnosis of the disorder.
These are also an important component of teeth,
ligaments and whites of the eyes (sclera).

27. Blue sclera

28. Osteogenesis Imperfecta and Genetics
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This condition typically results from a genetic mutation.
Medical research has been able to establish that the
genetic defect causing OI runs in families.
Type I of OI is a dominant inherited condition arising due
to mutations on chromosome 17 in the COL1A1 gene,
on chromosome 7 in the COL1A2 gene. This leads to
reduced manufacture of normal collagen.
This protein is a major constituent of the connective
tissues located within the bone
Hence OI chiefly characterized by symptoms like multiple
bone fractures, blue sclerae

29. Osteogenesis Imperfecta Diagnosis
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Physical examination of the sclera of the
eyes is usually enough to diagnose this
condition( bluish tinge). The condition is also
diagnosed with the help of other methods,
such as
DNA blood testing for gene defects has an
accuracy of 60-94%.
Prenatal DNA mutation analysis can be
performed in pregnancies with risk of OI to
analyze uncultured chorionic villus cells.

30. Osteogenesis Imperfecta Diagnosis
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Prenatal ultrasonography: Most useful in
evaluating OI types II and III by 2nd trimester.
Findings include bowing, shortening and
angulation of the long bones due to fractures
and easy visualization of intracranial
structures due to decreased ossification of the
skull vault.
3 important US criteria of specific diagnosis of
OI-type-II:
• a) FL greater than 3SD below the mean,
• b)Demineralization of calvarium,
• c) Multiple fracture within a single bone.

31. USG
D, Osteogenesis imperfecta type I. Isolated femoral fracture with acute angulation
(arrow).
F, Osteogenesis imperfecta type IIA. Bowed femur with multiple discontinuities
representing fractures.

32. OI Diagnosis-Plane radiography
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Obtain a radiographic skeletal survey after birth.
Generalized osteoporosis is present
In milder forms (Types I & IV)–Thin and gracile bones
with thin cortices. Skull vault may be normal.
In the more severe forms (types 2 and 3)-The bones
are thick and short with multiple fractures and
hyperplastic callus formation.
The skull is osteopenic and multiple wormian bones
are present. Multiple rib fractures may cause the bones
to become broad and deformed.
Platyspondyly and scoliosis are often present

33. Management
Genetic counseling is necessary for
couples who have a family history of
Osteogenesis Imperfecta (OI) and are
considering pregnancy.
Physiotherapy, rehabilitation, and
orthopaedic surgery are the mainstay of
treatment for patients with osteogenesis
imperfecta.
In recent years, biphosphonate therapy
has been used with success.

34. DIFFERENTIAL DIAGNOSIS
Battered baby syndrome:
Idiopathic juvenile osteoporosis

35. Battered baby syndrome:
Alternative name Child abuse/Non accidental trauma.
A young child, often under age 3, who has been
repeatedly and severely neglected by caretakers.
Battered children have signs of multiple episodes of
trauma—e.g., subdural haematomas, fractures,
bruises in various stages of healing—often with failure
to thrive and chronic malnutrition.
Fractures are usually metaphyseal. Multiple rib
fractures, fracture of scapula, sternum, vertebra, tibia,
metacarpal associated with intracranial injuries
(subdural haematomas).
Urinary hydroxypoline is not elevated.

36. Idiopathic juvenile osteoporosis:
Patient typically presents before puberty (8-
13 years) and have osteoporosis (lumbar &
thoracic vertebrae) that is progressive initially
and later stabilizes.
Vertebral compression fracture and
characteristically metaphyseal fractures
specially of lower limb bones occur.

38. Thank you

39. Osteogenesis imperfecta. Results from genetic
mutations causing abnormalities in Type I collagen, and
resulting in osteoporosis and low-trauma fractures
(brittle bone disease). The different types vary in clinical
presentation and severity.
Frontal view of the femora in an infant showing reduced
bone density and marked deformity due to multiple
fractures.
Lateral spinal radiograph in a 30-year-old man showing
reduced bone density and end-plate fractures of all
vertebrae. There is also evidence of a metallic pin in a
previous hip fracture. Osteoporosis is much less
common in men than in women, and more likely to be
related to secondary causes, especially excess alcohol
intake.

40. Radiological Features of Rickets
Radiological changes: Result from loss of orderly maturation
and mineralization of cartilage cells at the growth plate.
These changes predominate at the sites of bones which are
growing most active. These sites are – around the knee, the
wrist (particularly the ulna) , the anterior ends of the middle ribs,
the proximal femur and the distal tibia, and depend on the age of
the child.
Changes at growth plate and cortex
Widening of physis (earliest change)/growth plate.
loss of normal zone of provisional calcification adjacent to
metaphysis.
Irregular metaphyseal margins (Fraying)
Splaying and cupping of the metaphysis.
Indistinct cortex because of uncalcified subperiosteal osteoid.
Some expansion in width of the metaphysis results in the
swelling around the ends of the long bones .
Rachitic rosary.( This expansion and cupping of the anterior
ends of the ribs)
Looser’s zone is uncommon on children