Spinal Muscular Atrophy

Question 1

What is spinal muscular atrophy

Answer 1

Rare autosomal recessive condition which causes a progressive loss of motor neurons leading to progressive muscle weakness

Question 2

Presentation of SMA

Answer 2

Lower motor neurons affected so there will be fasciculations, reduced muscle bulk, hypotonia, reduced power, absent or reduced reflexes

Question 3

Age presentation of SMA type 1

Answer 3

Onset is first few months of life, usually death within 2 years

Question 4

Age presentation of SMA type 2

Answer 4

Onset within first 18 months, most never walk but survive into adulthood.
Most common type

Question 5

Age presentation of SMA type 3

Answer 5

Onset after first year of life, most walk without support but subsequently loose that abilty. Life expectancy almost normal

Question 6

Age presentation of SMA type 4

Answer 6

Onset in 20s, most will retain ability to walk but require wheelchair for long distances. Resp muscles unaffected