Unfortunately, there are actually people like this.
"Transabled" is a term some people use that wish to be disabled. There were even cases of people who paid doctors illegally to amputate a limb or they hurt themselves.
"Transage" are people who believe they actually have a different age. For example they feel like they are really 13. Some of them use that to justify relationships with minors.
They try to piggyback on the trans movement and present mental acrobatics in a whole new dimension of fucked up to explain why they are supposedly similar to people who are trans. (Which they really obviously aren't, I think that doesn't need explaining.)
And you can bet on it that trolls and right wingers use these obscure group of mentally unwell people to attack LGBTQ people and movements.