Hereditary Bone Conditions Flashcards
What is the most common form of Dwarfism?
Achondroplasia
What is the most common disorder of growth plates of the appendicular skeleton?
Achondroplasia
What gene is associated with decreased chondrocyte replications the growth plate in the most common type of dwarfism?
Autosomal dominant
(Fibroblast Growth Factor Receptor 3 (FGFR3))
What physical attributes do you expect to see in patients with Achondroplasia?
- Normal sized torso, but shortened limbs (Rhizomelic appearance)
- head>face
- depressed nasal ridge
- thoracic hyperkyphosis
- lumbar hyperlordosis
Do individuals with achondroplasia have a normal life expectancy?
Yes
What radiographic characteristics do you expect to see in patients with Achondroplasia?
- bullet vertebrae
- post. vertebral scalloping
- congenital central stenosis
- Hyperlordosis w/ horizontal sacrum when skeletally mature
- Short broad metaphysis
- Champagne glass appearance
- flat ilia (paddle-shaped)
Stenosis of the vertebral foramen is a major concern in what conditions?
Achondroplasia
What collagen synthesis disorder has an increased chance of developing mitral valve prolapse and dissecting aneurysms?
Marfan’s Syndrome
What gene mutation is commonly associated with Marfan’s Syndrome?
Autosomal dominant (FBN1 gene)
What are some of the clinical characteristics of patients with Marfan’s Syndrome?
- M>F
- Tall, slender individuals (long extremities)
- Arachnodactyly
- Hypermobile joints
- Scoliosis
- pectus excavatum (sternum in)
- pectus carinatum (sternum out)
What are some radiographic findings you would see with patients with Marfan’s syndrome?
- scoliosis
- elongated extremities (arachnodactyly)
- thin, gracile bones
- thin cortices
- delicate trabecular pattern
What inherited collagen synthesis disorder is also known as Brittle Bone disease?
Osteogenesis imperfecta
What type of OI is considered the most fatal and characterized by developmental defects including extremely brittle bones?
Osteogenesis Imperfecta Congenital
What type of OI is characterized by the anterior bowing of the extremities, the sclera of the eyes turning blue, and hearing loss due to bony deformities?
Osteogenesis Imperfecta Tarda
What conditions is characterized by the hypofunctioning of osteoclasts and is called Marble Bone Disease?
Osteopetrosis
What radiographic finding would you expect to see in patients with Osteopetrosis?
- Widening of metaphysis (“Erlenmeyer Flask” appearance)
- Lack of defined medullary cavity (radiopaque bone appearance)
- Sandwich vertebrae
What would you expect PTH levels to be in patients with Osteopetrosis?
Elevated (boobs)
In a normal, healthy individual, PTH will have what effect in the kidney?
Increase production of calcitriol
What is the heredity of cleidocranial dysplasia?
Autosomal dominant
Etiology of cleidocranial dysplasia
Mutation of gene that helps encode osteoblasts
Cleidocranial dysplasia results in deficiency of ____ ossification, affecting what bones?
Intramembranous
Flat bones (skull, clavicles)
What are the clinical features of cleidocranial dysplasia?
- large head, small face
- hypermobile shoulders (scapulothoracic)
- reduced height
- narrow, cone-shaped thorax
- hearing loss
- normal life span
What are the radiographic features of cleidocranial dysplasia?
- absent/hypoplastic clavicles
- pseudoarthrosis (mid portion missing)
- small, winged, elevated scapulae
- narrow, cone-shaped chest
What tool is used to assess hypermobility?
Beighton Questionnaire
Osteogenesis imperfecta has ____ genotypes, and ____ phenotypes
4
2
Osteogenesis imperfecta is a defect in…
Type I collagen synthesis
What are the clinical manifestations of osteogenesis imperfecta tarda?
- congenital osteoporosis
- blue sclera
- conductive hearing loss
- severe dental problems
What are the radiographic findings of osteogenesis imperfecta?
- mild to severe generalized osteopenia
- multiple fractures in various stages of healing
What is the heredity of osteopetrosis?
2 forms:
- autosomal dominant
- autosomal recessive
What are the clinical features of osteopetrosis?
- possible growth disturbances
- facial palsies (facial n compressed)
- neurogenic hearing loss (CN VIII compressed)
- dental caries
What are the possible complications of osteopetrosis?
- pathologic Fx
- anemia
- thrombocytopenia
- hepatosplenomegaly
- blindness/deafness/facial n palsies
- leukaemia & sarcomas
