A friend of mine's granddaughter is a few weeks younger than DS and has the same genetic mutation as DS; however, her symptoms were more upper respiratory in nature -- RSV, frequent upper respiratory infections, constipation. Whereas DS was born with a bowel obstruction caused by meconium illeus and he tends to have more sinus issues.
DS's sweat test as mentioned was 32, the granddaughter's I think was well over 100. They both have two copies of delta f508 yet sweat tests done as babies -- results were VERY different.