Kalydeco
"My nine-year-old son has G551D/deltaF508 CF. He began taking this at six years old, 2 years after it first became available in US.

 He went from being severely underweight to overweight in less than a year. His BMI is weighed over 95 percentile for age 9. 

His chronic cough went away within a week. He is not had any respiratory infections since beginning the medication. 

This medication is just short of a miracle for him. And I'm not exaggerating. I am a physician who has watched kids and young adults die of cystic fibrosis during my training."