MTHFR and Menkes disease: In MD, significant associations have been reported for polymorphisms in genes such as KCNE (in Japanese but not Caucasian populations), adducin 1 (Gly460Trp), heat-shock protein 70-1 (190G/C), interleukin-1A (−889C/T), AQP5, and MTHFR (C677T).