Congenital Disorders Flashcards
What is osteogenesis imperfecta?
Brittle bone disease
Defect of maturation + organisation of type 1 collagen
Which inheritance pattern does osteogenesis imperfecta usually follow?
Autosomal dominant
List clinical features of osteogenesis imperfecta
Fragility fractures
Short stature
Blue sclerae
Hearing loss
What is the medical term for short stature? (not dwarfism)
Skeletal dysplasia
What is the commonest skeletal dysplasia?
Achondroplasia
List the main clinical features of achondroplasia
Disproprotionately short limbs
Prominent forehead
Wide nose
Joint laxity
Connective tissue disorders usually affect type 1 collagen synthesis. Is bone or soft tissue usually affected?
Soft tissue
How does Marfan’s syndrome arise?
Autosomal dominant disease due to mutation of fibrillin gene
List clinical features of Marfan’s syndrome
Long limbs Ligamentous laxity High arched palate Scoliosis Pectus excavatum Cardiac issues
What is the defect in Ehlers-Danlos syndrome?
Abnormal collagen and elastin formation
List clinical features of Ehlers-Danlos syndrome
Hypermobility
Vascular fragility
Easy bruising
Which pattern of inheritance do muscular dystrophies usually follow?
X-linked recessive (only affect boys)
How does Duchenne muscular dystrophy (DMD) arise?
Defect in dystrophin gene (involved in Ca transport)
List the main features of Duchenne muscular dystrophy
Progressive muscle weakness
Difficulty standing (Gower’s sign)
Eventually unable to walk (by age 10)
People with DMD are prone to dying in their early 20’s - why?
Progressive cardiac and respiratory failure
How is diagnosis of DMD confirmed?
Raised creatinine phosphokinase
Abnormal muscle biopsy
At what age does cerebral palsy usually occur?
2-3yrs of age - insult to immature brain
List some potential causes of cerebral palsy
Genetic errors Brain malformation Intrauterine infection Prematurity Hypoxia Meningitis
Down’s syndrome involves trisomy of what chromosome?
21
In what way does Becker’s muscular dystrophy differ from DMD?
Milder - Boy can walk into their teens and live to 30s/40s
What are the 5 main types of cerebral palsy?
SPASTIC: motor paralysis (mono/hemi/di/quadraplegic) ATAXIC: cerebellar dysfunction ATHETOID: Uncontrolled writhing DYSTONIC: Repititive movements UMN: Weakness, spasticity, hyperreflexia
What is the most mild form of spina bifida?
Spina bifida occulta
What is the aetiology of spina bifida?
Incomplete closing of backbones and muscles around spinal cord before birth
What is the aetiology of polio?
Infantile paralysis caused by poliovirus - viral infection of anterior horn cells in spinal cord
