Congenital Disorders

Question 1

What is osteogenesis imperfecta?

Answer 1

Brittle bone disease

Defect of maturation + organisation of type 1 collagen

Question 2

Which inheritance pattern does osteogenesis imperfecta usually follow?

Answer 2

Autosomal dominant

Question 3

List clinical features of osteogenesis imperfecta

Answer 3

Fragility fractures
Short stature
Blue sclerae
Hearing loss

Question 4

What is the medical term for short stature? (not dwarfism)

Answer 4

Skeletal dysplasia

Question 5

What is the commonest skeletal dysplasia?

Answer 5

Achondroplasia

Question 6

List the main clinical features of achondroplasia

Answer 6

Disproprotionately short limbs
Prominent forehead
Wide nose
Joint laxity

Question 7

Connective tissue disorders usually affect type 1 collagen synthesis. Is bone or soft tissue usually affected?

Answer 7

Soft tissue

Question 8

How does Marfan’s syndrome arise?

Answer 8

Autosomal dominant disease due to mutation of fibrillin gene

Question 9

List clinical features of Marfan’s syndrome

Answer 9

Long limbs
Ligamentous laxity
High arched palate
Scoliosis
Pectus excavatum
Cardiac issues

Question 10

What is the defect in Ehlers-Danlos syndrome?

Answer 10

Abnormal collagen and elastin formation

Question 11

List clinical features of Ehlers-Danlos syndrome

Answer 11

Hypermobility
Vascular fragility
Easy bruising

Question 12

Which pattern of inheritance do muscular dystrophies usually follow?

Answer 12

X-linked recessive (only affect boys)

Question 13

How does Duchenne muscular dystrophy (DMD) arise?

Answer 13

Defect in dystrophin gene (involved in Ca transport)

Question 14

List the main features of Duchenne muscular dystrophy

Answer 14

Progressive muscle weakness
Difficulty standing (Gower’s sign)
Eventually unable to walk (by age 10)

Question 15

People with DMD are prone to dying in their early 20’s - why?

Answer 15

Progressive cardiac and respiratory failure

Question 16

How is diagnosis of DMD confirmed?

Answer 16

Raised creatinine phosphokinase

Abnormal muscle biopsy

Question 17

At what age does cerebral palsy usually occur?

Answer 17

2-3yrs of age - insult to immature brain

Question 18

List some potential causes of cerebral palsy

Answer 18

Genetic errors
Brain malformation
Intrauterine infection
Prematurity
Hypoxia
Meningitis

Question 19

Down’s syndrome involves trisomy of what chromosome?

Answer 19

21

Question 20

In what way does Becker’s muscular dystrophy differ from DMD?

Answer 20

Milder - Boy can walk into their teens and live to 30s/40s

Question 21

What are the 5 main types of cerebral palsy?

Answer 21

SPASTIC: motor paralysis (mono/hemi/di/quadraplegic)
ATAXIC: cerebellar dysfunction
ATHETOID: Uncontrolled writhing
DYSTONIC: Repititive movements
UMN: Weakness, spasticity, hyperreflexia

Question 22

What is the most mild form of spina bifida?

Answer 22

Spina bifida occulta

Question 23

What is the aetiology of spina bifida?

Answer 23

Incomplete closing of backbones and muscles around spinal cord before birth

Question 24

What is the aetiology of polio?

Answer 24

Infantile paralysis caused by poliovirus - viral infection of anterior horn cells in spinal cord

Question 25

What are the clinical signs of polio?

Answer 25

LMN deficit - weakness, reduced tone, loss of reflexes in limbs