What is the typical impact of Northern epilepsy syndrome (NE) on life expectancy?

A. Life expectancy is only moderately affected, with patients usually surviving past 40-50 years of age.
B. Life expectancy is significantly reduced, with most patients not surviving past 20 years of age.
C. Life expectancy is unaffected, with patients having a normal lifespan.
D. Life expectancy is severely reduced, with most patients not surviving past 10 years of age.
Answer: 