Symptoms are variable among affected individuals, but it is widely accepted that the soles of the feet, palms, and the face are never affected by mitempfindung. There is no evidence of genetic influence on referred itch.
This passage describes a condition called mitempfindung where symptoms vary among affected individuals, but it specifically states that the soles of the feet, palms, and face are never affected.  There is also no evidence suggesting a genetic component to the sensation of referred itch.