As a 15-year-old suffering from a rare genetic disorder that can leave her with severe burns after just 10 minutes in the sun, Lyndal Brown defied her parents' wishes in 2000 and attended a school summer camp in the Snowy Mountains. "I was sick of missing all the excursions, and preferred to get sunburnt than miss out again," says Brown, 24, who grew up in the NSW Blue Mountains. But, as her parents forewarned, "I got shockingly burnt and couldn't smile or even put a spoon in my mouth because my face felt like it was going to crack. I didn't sleep for a good week."

The excruciating pain wasn't a first for Brown, who, along with her sister, Angela Knight, 30, is one of some 350 Australians who have erythropoietic protoporphyria (EPP). Sufferers of the genetic condition, which involves a build-up of the chemical protoporphyrin IX in the skin, experience a painful burning sensation when exposed to the sun and some artificial light.

"Lyndal would rather put up with the pain than be recognised as different," says her mother, Wendy, 56, a housewife. "That affected her psychologically. Instead of saying, 'I'm in pain,’ and accepting she couldn't go in the sun, it became an inner turmoil."

These days, the student, who lives in the Blue Mountains with her husband, Jeremy, 27, avoids going outdoors. The pain of being burnt "feels like chilli on the skin or when you scald yourself with boiling water: real bad burning, stinging, itching," says Brown, who has had her car windows tinted to avoid being burnt while driving.

"A lot of the time I just don't do things." If she does go outside in the day, she must completely cover up with a hat, protective clothing, gloves and special clear zinc that, while not totally effective, is still better than standard sunscreen. Unless her sunburn is really severe, it isn't visible and the potential severity of burns varies day-to-day, depending on the level of porphyrins - molecules that help create red blood cells - in her skin and whether she has had alcohol or medications that make her more photo-sensitive. On a good day, she can spend a maximum of 30 minutes in direct sunlight.

For both Brown and her sister, who "were always told there was nothing we could do about it," help is on the way: Melbourne-based drug-development company Clinuvel has spent two decades creating a drug, which is implanted under the skin, that will stop them burning.

"I'm really excited," says Brown, who can count on one hand the number of times she has swum in the surf. "I love the beach, but it's torture because of the reflection from the water, which burns me even if I'm in the shade. I can't wait to go for a walk or camping and it not be torture."

The sisters have spent much of their lives, as Brown puts it, on the sidelines. "I got teased and felt different, angry, jealous, frustrated and lonely," she says. "We tried to pretend we didn't have it. I got used to saying to myself, 'Shut up, deal with it. No one understands, so there's no point telling anyone. There are people worse off.' "

Their mum encouraged indoor hobbies such as reading and piano playing, and Brown is undertaking much of her psychology degree at Charles Sturt University, Bathurst,

by correspondence. "Walking from the car park to classes was hard, but that's just an everyday experience," she says.

Despite her inhibited life, she considers herself lucky because she has known about
her condition from birth and, in her sibling, has someone she can relate to. "It's good
that we understand each other because most people don't," says Knight, a teacher who

is excited about the prospect of treatment, especially if her sons, aged 3 and 8, develop EPP later in life.

With the new drug, the sisters - they inherited the disease from their builder father, Ralph, 58, who doesn’t have EPP but is a carrier - can go camping and will say farewell to a game they've played since childhood. "We call it shadow jumping, where we run between the shadows," says Brown. "My dad's very good: he'll drive the car close so we can get in and don't have to go in the sun." For the whole family, it will be a new beginning. "I'd love to do little things like go for a walk when I want or play volleyball on the beach," says Brown. "Or hold hands with Jeremy at any time without feeling pain."