Genetic Disorders of MSK System Flashcards
What is osteogenesis imperfecta?
autosomal dominant defect of maturation and organization of type 1 collagen
What is osteogenesis imperfecta linked to?
fragility fractures in childhood, short stature, blue sclerae, loss of hearing
What do bones tend to be like in osteogenesis imperfecta?
thin with thin cortices, osteopenic
What is skeletal dysplasia?
medical term for short stature (used to be dwarfism)
can be proportionate or disproportionate
What is the commonest and most recognized type of skeletal dysplasia?
achondroplasia (disproportionately short limbs with prominent forehead and widened nose)
What causes connective tissue disorders?
genetic disorder of collagen synthesis, resulting in joint hypermobility
Name 4 subtypes of connective tissue disorders.
- Generalised (Familial) Joint Laxity - double jointed, more prone to reccurent dislocations of joints
- Marfan’s - autosomal dominant, sporadic mutation of fibrillin gene, tall with long limbs, hgh arched palate, scoliosis, flattening of chest, eye probz, AAA, cardiac
- Ehlers Danlos - profound joint hypermobility, vascular fragility, ease of bruising, bleeding is a problem
- Down syndrome - trisomy 21, short stature, joint laxity
In which, Ehler Danlos or Marfan’s is surgery more likely to be needed?
Ehler Danlos
What is Duchenne Muscular dystrophy?
defect in dystrophin gene involved in caldium transport - causes muscle weakness noticed when child starts to walk with difficulty standing - Gower’s sign
When do people with Duchenne muscular dystrophy normally die?
early 20s
What is the genetic link in muscular dystrophies?
X linked recessive
How is Duchennes diagnosed?
raised creatinine phosphokinase
abnormalities on muscle biopsy
What may prolong mobility in Duchennes?
physio, splints, deformity correction
