Atbash Self Palindromes

Pyth, 10 9 bytes

qJrz0_XJG

Try this fiddle online or verify all test cases at once.

Explanation

qJrz0_XJG
  rz0      Lowercase input
 J         Store a copy in J
     _XJG  Translate J with the reverse alphabet and reverse
q          Compare

RX, 9 8 bytes

Heavily inspired by Retina, I made this a few days ago. Code:

prR`w$rM

Explanation:

prR`w$rM

p         # Start pattern
 r        # Reversed lowercase alphabet
  R       # Reversed uppercase alphabet
   `      # Next pattern
    w     # Equivalent to a-zA-Z_0-9 (word pattern)
     $    # End pattern and compute regex
      r   # Reverse input
       M  # Change mode to Match mode, compares the atbash string with the reversed string.

Try it here!

Julia, 96 bytes

s->join([get(Dict(zip([u=map(Char,65:90);],reverse(u))),c,c)for c=(S=uppercase(s))])==reverse(S)

This is a lambda function that accepts a string and returns a string. To call it, assign it to a variable.

Ungolfed:

function f(s::AbstractString)
    # Get all of the uppercase letters A-Z
    u = map(Char, 65:90)

    # Create a dictionary for the transformation
    D = Dict(zip(u, reverse(u)))

    # Uppercase the input
    S = uppercase(s)

    return join([get(D, c, c) for c in S]) == reverse(S)
end