Tracey Campbell, of Rett UK, said Romi had been dismissed in many areas of her life and she wanted to prove she was capable.
“To have these extra barriers put in place is completely unfair and unjust,” she said.
“What has been fabulous about exam boards in England is that people have been allowed to sit their exams over a long period of time, one question at a time.”
Glasgow Clyde College, where Romi studies, said she is “highly capable and committed”.
Claire Donaghey, assistant principal arts and continuing education, said: “Despite considerable discussion with Qualifications Scotland, the mitigating arrangements we have proposed have not been deemed compatible with these requirements.
“We remain fully committed to supporting Romi and will continue to work constructively with her, her family and Qualifications Scotland to explore every available option and achieve the best possible outcome for her.”
Qualifications Scotland said it was committed to making reasonable adjustments so that disabled learners have an equal opportunity to demonstrate their knowledge, skills and understanding.
A spokesperson said: “This year over 39,000 learners benefited from assessment arrangements.
“We also have a duty to maintain the integrity of qualifications, so must always ensure that any reasonable adjustments put in place for learners do not impact standards.”
