CSNB

Question 1

what are the

common findings

and differences

between complete and incomplete CSNB

Answer 1

• common findings
  
  • normal fundi
  • electronegative ERG (a>b wave)
• DIFFERENCES:
  
  • inheritance
    
    • complete X-linked or AR
    • incomplete: x-linked only
    • so if you see an AR inheritance it must be complete
  • mutations
    
    • x-linked complete = NYX
    • x-linked incomplete = CANA1f (calcium channel)
  • ERG
    
    • on response affected only (complete
    • on & off affected (incomplete)