Developmental Bone Disorders Flashcards
Genu varum, kyphosis, trident hand, and stenosis are associated with…
Achondroplasia
What is the gene mutation for Achondroplasia?
FGFR-3 defect
What is the MOA of the Achondroplasia defect?
FGFR-3 defect on chromosome 4
Mutation substitutes an Arginine for a Glycine
Functions as a transmembrane receptor at the physis
“Without Cartilage Formation”
Achondroplasia
Foramen Magnum Stenosis, thoracolumbar kyphosis, spinal stenosis, genu varum, short stature
Achondroplasia
Where does kyphosis occur in Achondroplasia?
thoracolumbar region
Bowing of the knees (genu varum) is associated with…
Achondroplasia
Osteopetrosis is a problem with…
not breaking down or resorbing bone
What cells are involved with osteopetrosis?
Defect in osteoclasts
Is achondroplasia genetic?
Yes.
Osteopetrosis is a _____ disorder and is also known as ______
Genetic
Marble Bone Disease
What defect is related to osteopetrosis?
defect in osteoclast resorption –> dense and brittle bone
root cause:
defect in acidification of bone –> defect in osteoclast function
Malignant or infantile Type Osteopetrosis is a mutation in… with inheritance pattern of…
Gene: TCIRG1
Autosomal recessive
TCIRG1 mutation leads to…
proton pump defect
Osteopetrosis that presents in infancy, severe osteosclerosis, hearing loss, visual loss, anemia, death in first decade
Malignant or infantile Type Osteopetrosis
Intermediate Osteopetrosis
Autosomal recessive
Mutation in CLCN7 and CAII
CLCN7 is associated with…
function of chloride channel
CAII is associated with function of…
carbonic anhydrase II
Benign or autosomal dominant osteopetrosis type II
autosomal dominant
CLCN 7 mutation
Renal acidosis, cranial nerve palsies, cerebral calcification
Intermediate Osteopetrosis
frequent fractures, coxa vera, back pain
Benign
Rugger Jersey Spine
Osteopetrosis
dense bone, can’t see through it in x-ray
Osteogenesis Imperfecta is commonly associated with a defect in…
COL1A, abnormal collagen
Type I collagen is found in…
bones, teeth, ligaments, sclera
Imperfect growth of bone =
Osteogenesis Imperfecta
Lobstein disease, brittle bone disease, blue sclera syndrome, fragile bone disease =
Osteogenesis Imperfecta
Osteogenesis Imperfecta is associated with defect in…
COL1A gene
type I collagen production
both quality and quantity
Osteogenesis Imperfecta has an inheritance pattern of…
autosomal dominant for COL1A
some autosomal recessive
others, sporadic
Skin punch biopsy or blood test can be used to diagnose…
Osteogenesis Imperfecta
What are the most common forms of Osteogenesis Imperfecta?
Type I and III
Physical exam findings of: blue sclera, traigular facies, defective dentition, macrocephaly, scoliosis, limb deformities, joint laxity
hearing loss, growth retardation
Osteogenesis Imperfecta
You have to rule out other diagnoses such as non-accidental trauma when considering diagnosing…
Osteogenesis Imperfecta
Lab evaluation for Osteogenesis Imperfecta include…
microscopic analysis of collagen synthesis
DNA analysis for COL1A mutation
DNA testing in fetus (60-94% accuracy)
Skin punch biopsy
You can detect what types of Osteogenesis Imperfecta with prenatal ultrasonography?
Type II and III
Prenatal Ultrasonography for Osteogenesis Imperfecta is best if done at…
15-18 weeks gestation
In prenatal ultrasonography for Osteogenesis Imperfecta, you’ll see…
visualization of intracranial contents
bowing of long bones
rib fractures
shortened femurs
Radiographic findings associated with Osteogenesis Imperfecta include…
wormian bones
enlargement of frontal and mastoid sinuses
platybasia (flat base of skull) with or without basilar impression
Pectus carinatum is associated with…
Osteogenesis Imperfecta
Narrow pelvis, protrusio acetabuli (ball is punching outward), and shepard’s crook deformity of femurs is seen in….
Osteogenesis Imperfecta
What disorder has individuals healing well but healing with bone that doesn’t function correctly?
Osteogenesis Imperfecta
What is a treatment option for Osteogenesis Imperfecta?
Bisphosphonate infusion
What will you see in an x-ray for bisophosphonate infusion?
hard line of bone in radiography
olceranon fractures are uncommon and distinguishing for…
Osteogenesis Imperfecta
Bisphosphonate use results in…
increased trabeculae and cortical thickness
increased bone density
improved vertebral morphology
What treatment helps with decreasing fractures and deformity of bones for Osteogenesis Imperfecta and other disorders?
Bisphosphonate infusion
Bisphosphonate infusion is used mostly for what type of Osteogenesis Imperfecta?
Type III- the worst
What are other therapy options for Osteogenesis Imperfecta?
Vitamin supplementation- calcium, phosphorus, vit D
Surgery- straight bones and intramedullary implants
What are the available types of implants for surgery of Osteogenesis Imperfecta?
Expandable- Baily Dubow Rods and Fassier Duvall Rods
Non-Expandable- Rush Rods and Flexible Nails
What are future directions for treating Osteogenesis Imperfecta?
Bone marrow transplants
Stem cell therapy
Gene therapy
What disorder is linked to defect in FBN-1
Marfan Syndrome
Marfan Syndrome is…
Heritable
Genetic defect in FBN-1
Abnormal collagen production and elastin
Tall stature, aortic root dilitation, hypermobility, optic lens dislocation, striae are associated with…
Marfan Syndrome
Ehlers-Danlos is a…
heritable disorder with some similarities to Marfan but not as bad
Ehlers-Danlos is a defect in
collagen and elastin
Fragile Hyperelastic Skin, joint hypermobility, early development of OA, painful joint dislocations are associated with…
Ehlers-Danlos
Major criteria for Ehlers-Danlos include…
small finger hyperextension
thumb touches forearm
elbow hyperextension
knee hyperextension
trunk flexion
Minor criteria for Ehlers-Danlos include…
More than one instance of joint sublaxation or dislocation
more than 3 soft tissue tendinopathies
abnormal skin with striae (stretch marks) or hyperextensibility
Acoustic neuromas as associated with…
Neurofibromatosis Type 2
Neurofibromatosis Type I is a genetic mutation on which chromosome?
17
von Racklinghausen
NF-1 disorder
Neurofibromatosis Type I is an autosomal-_____
dominant disorder
Cafe-au-lait spots, neurofibromas, freckling, optical glioma, lisch nodules, bone lesions, family history of disorder are related to…
Neurofibromatosis Type I
Neurofibromata are made up of which cell type?
Schwann cells and fibrous tissue
rarely causes problems
Plexiform neurofibromas are…
very vascular and can lead to disfigurement and gigantism
What type of bowing is seen in Neurofibromatosis Type I?
Antero-lateral bowing of tibia which can fracture and get pseudoarthroses
What type of bracing should be used for Neurofibromatosis Type I and associated antero-lateral bowing of tibia?
clamshell bracing for tibia
What type of scoliosis is most commonly associated with Neurofibromatosis Type I?
Dystrophic
Dystrophic scoliosis is associated with…
short and sharp angulation
Tibial bowing seen in ______ should be fixed with clamshell brace that fixes with a _______ _______ device
Neurofibromatosis Type I
load sharing
Neurofibromatosis Type 2 is associated with a mutation in…
Schwannomin gene
Type 2 is associated with fewer…. but more….
neurofibromas
intracranial lesions- explains the acoustic neuromas being more common
