に至いたっては

expression

when it comes to; as for; in the case of

Used to single out an extreme or notable example, often with a sense of 'even' or 'especially'. It can carry a negative or surprising nuance, implying that the mentioned case is particularly remarkable or problematic.

See also: 至る

• 彼かれは普ふ段だんは温おん厚こうだが、に至いたっては怒いかりを爆ばく発はつさせた。

  He is usually gentle, but when it came to that, he exploded in anger.

• この店みせの料りょう理りはどれも美味おいしいが、に至いたっては絶ぜっ品ぴんだ。

  All the dishes at this restaurant are delicious, but this one in particular is exquisite.