The phrase "in a variant" is correct and can be used in written English.
It is often used when discussing different versions or variations of something. Example: "The researcher compared the results in a variant of the experiment using a different methodology."
They always resurface, if sometimes in a variant strain.
In a variant of Stockholm syndrome, his position is at once open and deceitful.
It is an intellectual error because it indulges in a variant of American exceptionalism.
He has a distinctly skimpy costume that is twisted on the top of his head in a variant of the Phrygian cap.
Through luck rather than virtue, for the most part, we happen to live in a variant that has succeeded better, so far.
The United States has again produced a world champion, though not in regular chess, but in a variant named for Bobby Fischer.
In a variant of that method, the deflection of the balance is maintained constant by a servo control.
At his most derivative, Anderson throws in a variant of a famous scene in Hitchcock's espionage thriller "The Lady Vanishes," in which armed, uniformed Fascists gather outside a stopped train.
So far, we are following the script from 1996, when Britain issued a warning about a rise in a variant of Creutzfeldt-Jakob Disease, a brain-wasting syndrome in humans that resembles mad cow disease.
In a variant of "Road Warrior" or maybe "Alien," a group of party stalwarts from Boise and Salt Lake City and Jackson and Dallas and Kennebunkport is dropped down in the middle of that same gritty Philadelphia.
In a variant on my point above, one way of describing the observed trend is "less frequent violent outbursts, but more deadlier outbursts when they come".
