"trans racial" could be considered a thing in practice, in the sense that people adopt cultural racial signifiers and will even change their skin tones and use cosmetic procedures to look more like another race (derogative terms to shame behaving or looking like another race like "wigger" come to mind). However, clearly the experience that one is actually another race than what others perceive them as isn't as common or apparently as important to anyone's identity as gender identity is for trans people, so that I've never seen somebody who is clearly of some western European descent saying they're black. Also, attempts to adopt the physical characteristics or cultural characteristics associated with another race are usually made for the purpose of social advancement. Michael Jackson is at least an example of this on the perceptions side, since it seems commonly believed that he bleached his skin and got plastic surgery because he didn't want to be black. But this isn't to equate the two, rather to point out that as obvious as it is that race is a sociological relationship it is also easy to point out instances of behavior and perceptions of other people as being "transracial". To go back to Michael Jackson, would anyone who didn't know he was black think that he was black without being shown a picture of him in the past? I've also heard several people question whether or not Ariana Grande is black, for instance. And in the same sense the interstices of physical sex characteristics and gender norms can result in people who are "transgender", who do not conform to the common understanding of what it means to be a man or woman, although they may either themselves actively identify as one or the other or may be percieved as one or the other. But this doesn't necessarily mean that characteristics associated with either gender or race are located somewhere in the brain such that you can observe a given brain and identify what race or gender it belongs to. From what I understand, Male and female brains are almost indistinguishable from each other. It is very likely that a neuroscientist observing the brain of any given man, outside of obvious overall size differences due to differences in average body mass, would be unable to distinguish it from a woman's brain.