An English schoolgirl who suffers from a rare neurological condition has missed nine of her final exams after dozing off in April and not waking up until last week.
Stacey Comerford, 15, has Kleine Levin Syndrome, or Sleeping Beauty Syndrome, which can cause her body to enter a sleeping state for months at a time, The Daily Mail reports.
"I've missed nine exams and my birthday in November," Stacey said.
The teen has lost over 12 kilograms because of the condition and her mother has even been investigated by school authorities, who thought she was keeping her daughter out of school.
Her mother, Bernie Richards, said during her long stints of slumber Stacey got up to drink water and use the bathroom but was in an unresponsive trance-like state.
"When she’s in sleep mode she can be quite moody but she can’t help it. She’s like a toddler who wants to do things her own way. She stamps her foot if she doesn’t get what she wants," she said.
When Stacey wakes up she has no idea how long she has been asleep.
She began experiencing symptoms a year ago but was only diagnosed in March.
Doctors initially thought Stacey was just another moody teen who liked to sleep.
"The GP said 'I know it sounds awful but she looks like a moody, depressed teenager'," Ms Richards said.
A neurologist diagnosed her with the condition after initially suspecting a brain tumour.
There is no cure for Sleeping Beauty Syndrome but some sufferers have grown out of the disease.
The University of Newcastle’s Professor Joerg Mattes told ninemsn the syndrome was "quite rare", with about one in 20 million people diagnosed with it.
"When you think about the figures, it would almost suggest there wouldn’t be many Australians suffering from it," he said.
"It affects more males than females."