は別(べつ)としてApart from, (Setting) aside, Whether or, Except for, Save for

は別(べつ)として is a set phrase with the meaning of 'setting aside (A)', 'except for (A)', or 'save for (A)'. This structure combines は, 別(べつ), a noun meaning 'difference', 'separation', or 'distinction', と, and the て-form of する. Due to this combination, the more literal meaning is 'going ahead with (A) as an exception', and just declares that (A) is something that is being completely disregarded before discussing the main point.

As は is simply marking the topic in the same way that it usually does, this phrase may be seen after a noun, or any other word that would usually be grouped with は. This frequently includes things like かどうか.

It is also fairly common to see the (A) word repeated in both its positive and negated form. This has the nuance of 'whether or not', in the same way as かどうか.

Despite this grammar structure being used to essentially remove (A) from what is being discussed, the primary reason for this is that (A) is usually an exception to some particular rule or constant that the speaker wants to highlight.

Caution

は別(べつ)として may occasionally be replaced by は別(べつ)にして, with little change in overall nuance. The use of と merely sounds more definitive, while に expresses that the speaker is intentionally separating (A).