Genetic disorders Flashcards
What is osteogenesis impefecta?
A defect of the organisation and maturation of type 1 collagen
What are the signs of osteogenesis imperfecta?
Multiple fractures in childhood
Short stature
Blue sclera
Multiple deformities
What are the implications of having the autosomal recessive type of osteogenesis imperfecta?
Fatal in perinatal period
Spinal deformity
What is skeletal dysplasia?
Short stature due to a genetic defect resulting in abnormal development of bone and connective tissue
What is the most common form of skeletal dysplasia?
Achondroplasia
What deformities does achondrooplasia result in?
Disproportionately short limbs
Prominent forehead
Wide nose
What other complications can skeletal dysplasias be associated with?
Learning difficulties Spine deformity Limb deformity Internal organ dysfunction Craniofacial abnormalities Skin abnormalities Tumour formation (especially haemangiomas) Joint hypermobility Atlanto‐axial subluxation Spinal cord compression (myelopathy) Intrauterine or premature death
What is Marfan’s syndrome?
Autosomal dominant or sporadic mutation of the fibrillin gene resulting in tall stature with disproportionately long limbs and ligamentous laxity
What are some of the features of Marfan’s syndrome?
High arched palate Scoiliosis Pectus excavatum Eye problems (lens dislocation, retinal detachment) Aortic aneurysm Cardiac valve incompetence
What is Ehlers-Danlos syndrome?
A heterogeneous condition which is often autosomal dominantly inherited with abnormal elastin and collagen formation
What are the features of Ehlers-Danlos syndrome?
Profound joint hypermobility
Vascular fragility with ease of bruising
Joint instability
Scoliosis
What must be considered when giving surgery to a patient with Ehlers-Danlos syndrome?
Greater risk of bleeding
Poor wound healing
Wound dishiscence
What are muscular dystrophies?
These are rare and usually X‐linked recessive hereditary disorders (therefore only affecting boys) resulting in progressive muscle weakness and wasting
What is Duchenne muscular dystrophy?
A defect in the dystrophin gene involved in calcium transport results in muscle weakness which may only be noticed when the boy starts to walk with difficulty standing and going up stairs
What is the progression of Duchenne muscular dystrophy?
Presentation when starting to walk with difficulty standing and going up stairs
Progressive muscle weakness follows and by the age of 10 or so he can no longer walk and by age 20 progressive cardiac and respiratory failure develop with death typically in the early 20s
