https://www.reference.com/science/can-boy-girl-identical-twins-f20c37b6ec0408c1
I read somewhere that the boy of the twin pair can be affected also so that he has only a Y chromosome, but that is not mentioned in this article.
https://www.mun.ca/biology/scarr/2250_Chromosome_Genetics_2016_short.html
chromosome missing
...non-disjunction in meiosis
......X (XO) humans: Turner Syndrome ( 2n = 45, X)
......Y (YO) humans: fatal in utero
YO non-viable fetus
Don’t like the thought of that
Most Turner’s cases are singletons, not twins. And the linked article on ‘twin’ cases can’t qualify as ‘identical’ twins. Even though the somatic chromosomes would be identical as would the shared X chromosome the non-shared Y would render them non-identical at first glance in the delivery room and also by even rudimentary genetic testing. And they’d diverge further over time as the genetically normal brother would grow normally whereas his sister would stay short, even by girl standards, as well as display the signs of Turner’s. Although they’d probably be easily recognizable as siblings.