DS had a mid-year skip last year from 1st to 2nd. The only obvious gap he has is a year less of handwriting motor skills. Though when comparing his handwriting to others in his class, he now sits solidly in the middle of the pack. You wouldn't be able to tell but I can tell.
I believe he missed an entire semester of social studies in the skip. But we spent a week in DC on vacation so I'm pretty sure we covered all of it and more.
He'll be subject accelerated a year in math this year as well (so 2 years technically). From what I've noticed, his math is actually gap-free, since he uses traditional vocabulary and does math the "old" way without lattice or scales or whatever!
