Provided herein in some embodiments is a non-naturally occurring variant of a wild type restriction enzyme defined by SEQ ID NO: 20, wherein the variant has at least a 2 fold increase in cleavage at 5-β glucosylhydroxymethylcytosine (5βghmC) compared with methylcytosine relative to the wild type enzyme. Methods for examining hydroxymethylation of a DNA sample using the variant enzyme are also provided.