Zusammenfassung der Ressource
Osteogenesis
Imperfecta
(OI)
- Pathophysiology
- OI is an inherited connective
tissue disorder that primarily
affects bone (Martin &
Shapiro, 2007). It is caused by
mutations in various collagen
producing genes (Rush,
2016). There are currently 8
known types.
- Mutations in
COL1A1,
COL1A2,
CRTAP, and
P3H1 genes
cause OI (GHR, 2018)
- COL1A1 and COL1A2
genes, cause more then
90% of all cases of OI,
and are inherited via an
autosomal dominant
pattern (GHR, 2018).
- COL1A1 and
COL1A2 provide
instructions for
making proteins
that are used to
assemble type I
collagen (GHR, 2018).
- OI can also have an
autosomal recessive
pattern of inheritance,
especially when it is
caused by mutations in
the CRTAP or P3H1
gene, which cause
rarer, severe forms of
OI (GHR, 2018).
- Proteins produced from
CRTAP or P3H1 genes process
collagen into its mature form,
therefore mutations in them
disrupt the normal folding,
assembly, and secretion of
collagen molecules, thus
weakening connective tissues
(GHR, 2018).
- Infants with more severe
forms of OI, including type II
and III, have no family history
of OI. In these infants, the
condition is caused sporadic
mutations in the COL1A1 or
COL1A2 gene (GHR, 2018).
- The etiology of OI
type V and OI type
VI is unknown, as
there are currently
no identified
mutations causing
them (GHR, 2018).
- Epidemiology
- Nursing Considerations
- Psychosocial Support
- Reassure
parents not to
feel guilty
regarding child’s
diagnosis &
refer to genetic
counsellor
- Educate
parents on how
OI does not
affect a child’s
ability to think
and learn
- Offer various resources such as:
Osteogenesis Imperfecta
Foundation website
(www.oif.org) and phone
number: 1-800-981-2663 -
Referrals to local OI support
group, pediatrician, pediatric
orthopedist, physical therapist
should be provided
- Handling
- - Educate parents with demonstration
and explanation of proper holding,
lifting, feeding and general infant care
procedures - Get to parents to do a
return demonstration to ensure
learning has occurred - Provide reading
material and educational resources
such as brochures from OI foundation
etc. - Provide teaching regarding
recognizing new fractures and
protecting the injured body part while
travelling to the hospital or clinic -
Advise parent regarding choosing
clothing with wide openings since it’d
allow for the garment to slide over the
infant’s arms or legs without pulling the
limbs
- Bedding and positioning
- Waterbeds and soft bedding should
never be used - Regular crib
mattress is recommended for a
baby with OI - Position the infant to
prevent plagiocephaly: use rolled
blankets/sheets or soft foam to
support side lying position
- Parent teaching
- - Educate parents with demonstration and
explanation of proper holding, lifting,
feeding and general infant care
procedures - Get to parents to do a return
demonstration to ensure learning has
occurred - Provide reading material and
educational resources such as brochures
from OI foundation etc. - Provide teaching
regarding recognizing new fractures and
protecting the injured body part while
travelling to the hospital or clinic - Advise
parent regarding choosing clothing with
wide openings since it’d allow for the
garment to slide over the infant’s arms or
legs without pulling the limbs
- Feeding
- - Small, frequent feeds: babies may
be poor feeders and may have weak
sucking reflex - Breast milk
recommended: excellent source of
nutrition • Fosters special bond
between mother and child • If infant
unable to breastfeed due to inability
to suck or risk of aspiration due to
rapid respirations: offer mom to
pump breast milk and feed the child
from a bottle - Burp the baby
cautiously: gently lift the baby and
soft taps with padding over hands
are recommended
- Clinical Manifestations
(OI, n.d.)
- Type I: Most
common/
mildest form
- Bones break easily,
usually before
puberty, but
minimal bone
deformity
- Sclera have
a grey,
blue, or
purple tint
- Brittle
teeth
- Decreased
amount of
collagen, but
normal
structure
- Muscle
weakness
- Spinal
curvature
- Hearing
loss,
starting in
the 20s-30s
- Triangular
shaped
face
- Type II:
Most
severe
- Death at birth, or
soon after birth,
as a result of
respiratory
compromise due
to under
developed lungs
- Small
stature
- Many
fractures &
severe bone
deformity
- Abnormally
structured
collagen
- Tinted
sclera
- Type
IV
- Similar to Type
I & III, with
whiter sclera
- Type III
- Similar to
Type I
- Bones fracture
easily, with fractures
present at birth
- Possible
respiratory
issues
- Barrel-shaped
rib cage
- Improperly
formed
collagen
- Type
V
- Similar to
Type IV,
with
normal
teeth
- Bone has
mesh-like
appearance
under
microscope
- Restricted
forearm rotation
due to
calcification of
the interosseous
membrane
- Abnormally
large
hypertrophic
calluses at
fracture sites
- Radio-opaque
band seen on
growth plate
of long bones
- Type
VI
- Similar
to Type
IV
- Bone has a
fish scale
appearance
under
microscope
- Type
VII
- Similar to Type IV,
but results from
recessive
inheritance of a
mutation to the
CRTAP gene (Ward
et al., 2002)
- Type
VIII
- Similar
to Type I
or II
- White
sclera
- Extreme
skeletal
under
mineralization.
- Severe
growth
deficiency
- Treatment
- Diagnosis:
(NIH, n.d.)
- OI diagnosed
prenatally, at birth or
at a young age,
unless the condition
is a milder form, in
which diagnosis can
take place in the
teenage or adult
years (OIF, 2015)
- Family
history
- Clinical presentation
(Frequent fractures,
sclera colour change,
teeth deformities,
hearing loss, etc.)
- X-rays: fractures
that are at
different stages of
healing; Wormian
bones of the skull;
"codfish
vertebrae" of the
spine
- Biochemical
testing:
collagens taken
from a small skin
biopsy, where
changes in type I
collagen are an
indication of OI
- DNA sequencing: COL1A1
and COL1A2 is used to
identify the type I collagen
gene mutation
responsible for the
altered collagen protein
Children need additional
testing of less common
collagen genes (CRTAP
and P3H (LEPRE1))
responsible for some of
the rare recessive forms
of OI