Emily Brontë may have had Asperger syndrome, according to the literary biographer Claire Harman.

At an event at the Edinburgh international book festival, Harman, author of the recent biography Charlotte Brontë: A Life, said several of Emily’s character traits, including her genius, her dislike of leaving home, her discomfort in social situations and her sudden bursts of anger and frustration could have been symptoms of Asperger’s.

One famous case of Emily’s anger was recorded by Charlotte Brontë’s first biographer and fellow author Elizabeth Gaskell, who in her 1857 biography recalled how the family dog was left “half blind and stupefied” after Emily punched it in the face for dirtying the laundry. But Harman said on Sunday that Gaskell related the incident as “just a sign of Emily’s strength of character”.

“It is actually very disturbing. I think Charlotte and everybody was quite frightened of Emily. I think she was an Asperger’s-ey person,” Harman said. “She was such a genius and had total imaginative freedom ... Containing Emily, protecting Emily, not being alarmed by Emily, was a big project for the whole household. She’s an absolutely fascinating person – a very troubling presence, though.”

Even more than reclusive Charlotte, Emily hated leaving home, Harman said, which was why they hoped, for a while, to start a school from their home at Haworth, West Yorkshire.

The Yorkshire village of Haworth, home to the Brontë family. Photograph: Travelib Europe / Alamy

At the event, Harman also dismissed the theory that all the Brontë books were written by one sibling, and that Emily’s brother Branwell wrote part of Wuthering Heights – an idea Harman said only existed because the novel was “so peculiar”.

“Being Emily Brontë is enough. Emily Brontë was an amazing genius. One of the problems of writing about Charlotte Brontë was, I thought, ‘Hang on, being Emily Bronte’s sister would be enough to have a book written about you, wouldn’t it?’” Harman said.

“People do tend to sentimentalise [Emily]. They say their favourite romantic novel is Wuthering Heights, but it is so full of violence, so full of things I would not classify as romantic at all.”

The Wuthering Heights author shared many behavioural qualities with her father Patrick. “He gave them an immense latitude in terms of his interest in issues of the day that transferred very readily. The children liked nothing more than to read a parliamentary report around the fireside. They were a very unusual family in that respect, and he did not restrain them intellectually. But he was a very chilly man, very emotionally strange. He was clearly hugely egotistical and I think, also a bit Asperger’s-ey too.”

After writing the biography of Charlotte in the lead-up to her 200th birthday this year, Harman said she was looking forward to the inevitable range of biographies about Emily in two year times. “It is Emily Brontë’s bicentenary in 2018 – it’s too late for me to write another book I’m afraid, but I am looking forward to what people produce because she is such an extraordinary person.”