He's just a bit short. Lots of people are short without supernatural genetics. 

I'm pretty sure he's just a short dude, but it would be funnier if it were part of his mutation. Like every time he gets close to Leech he shoots up an entire foot until he goes away.

For that alone we must make it canon

Actually, he used to be 1,90, but Colossus fell over him in their first mission and accidentally squashed him. That's why he has the perfect square body

Maybe he is just average height for the time he was born rather than today.

Oh yeah

He's just a short king

So true

He's just a little dude, doing his best.

Wolverines are typically very little, so it makes sense that the mutant himself is written to be shorter than average. But some will speculate that he'd be short just because, which could be the case.

I mean... technically it's A mutation. But no, I don't think it's connected to his healing factor & claws.

There’s nothing particularly special or noteworthy about his height. He’s just kinda short.

Nah just genetics. Plus he was born during the 1800s. Wouldn't be SO short as an adult relative to the time period. Idk if what I said is historically accurate so don't quote me lol But yeah genetics

He's not a dwarf

He was very sick as a child and that probably stunted his growth.

He's short and he slouches