A 52W low with a Gap seems to be a recent trend that I have noticed. I am going to be watching these stocks as they seem to bounce back to at least the high of where the initial gap down occured. 

I am going to be watching 1: what the stocks initially do the day after the gap. 2: What the stocks do after the day of a 52W low. and 3: How the market reacts to the level of resistance heading into the gap

A good example today was $CYTR. It took 19 trading day AFTER the initial gap down in order for the stock to fill the gap.

What was the reason for the stock to start to uptrend after the initial gap down?

This was a news event that actually gapped the stock up. A news event regarding a positive Phase 3 trial outlook

Was there any news that led to the gap fill?

No. No specific news regarding any updates was given for the stock to spike up to fill the gap

Once the break of the gap resistance the stock jumped over 20% within 2 days

These are the type of stocks that I will looking at to see how they react when the resistance level of the gap to fill is broken. Charts are listed below: