Kathy Lette and son Julius

Kathy Lette and son Julius, who has Asperger's syndrome. Photo: Supplied

I'm expecting Kathy Lette to come at me a mile a minute. Her reputation as queen of the quip precedes her; it seems she's always up for a laugh, a woman who met the (real) Queen dressed in corgi-print ensemble, complete with geranium pot handbag, a woman who keeps the British establishment on its toes. Her latest book, The Boy Who Fell to Earth, is a frantic story, full of gags. Typical Lette.

But at the same time, it's a serious story, about a single mother raising a son with Asperger's syndrome. And it's a story that's very close to home.

Julius, the oldest child of Lette and her husband Geoffrey Robertson, has Asperger's, and while she insists her 11th novel is a work of fiction, you get a sense that Lette has just let go of a breath she's been holding for 21 years.

''It's been so cathartic actually,'' she says. ''I've always said that I only write because it's cheaper than therapy. And in this case, it really is true. I feel so relieved that I've come out about my real life. I never intended to write this book … but two years ago I started writing my next comic novel, and suddenly this other story came pouring out of my pen.''

She says she planned from the outset to treat the book as fiction, and refrain from mentioning the personal angle. She wanted, ultimately, to let the book stand alone ''on its own two literary legs'', until a journalist asked her directly whether there was any truth to the story.

''I was flummoxed. Lying would imply that I'm embarrassed of my child and the opposite is true. I am fiercely proud of him,'' she says.

''In order to protect Jules's privacy, neither Geoff nor I have ever talked about him publicly. But he asked me recently why his father and I speak about our daughter Georgie in the papers, but never speak about him in the press. Well, that just cut me to the quick.''

Jules's ability to speak the truth has always been a part of who he is, says Lette, for better and worse.

''People with 'Asparagus syndrome', as he calls it, see life through the other end of the telescope. And their logic can be charmingly disarming,'' she says.

''My son is always asking me the most interesting questions. When he was five, he wanted to know 'What is the speed of dark?' And, 'If onions make you cry are there vegetables which make you happy?' I doubt it enhanced his educational prospects when my son asked his intimidating headmaster what he wrote on his drivers licence for hair colour, seeing as he was completely bald.''

Such frankness, she says, often leaves her ''sweating more than Paris Hilton doing a sudoku''.

''As you can imagine, this quirky candour makes for many comical social situations which I tried to capture in the novel. But basically, when parenting a child with Asperger's, it's best to just strap a shock absorber to your brain. Because Aspergic people have no filter - they always say exactly what they're thinking, which means parents are constantly tiptoeing through a social minefield. You never know when you will touch a trip wire.'' Asperger's is a developmental disorder within the autism spectrum, and is often characterised by good verbal skills, but poor communication, a difficulty in sustaining social interactions and a lack of emotion and empathy. While a rate of incidence is hard to determine due to the number of people who go through life undiagnosed, experts suggest it may be as common as one in 250. Lette says raising a child with Asperger's is ''a bit like raising a Martian. You sometimes feel as though you didn't give birth to such a child, but found him under a spaceship and are now raising him as your own.''

In Lette's book, the heroine, Lucy, goes into denial when her son Merlin is diagnosed with Asperger's and Lette remembers feeling the same way.

''The initial diagnosis pulls you into the riptide and drags you down into the dark,'' she says. ''When I got the diagnosis, it was as though my son had become a plant in a gloomy room and it was my job to pull him into the light. I felt disbelief, followed by dismay and then by a fiercely protective lioness-type love.

But denial is a common response … hence the years of trudging through a labyrinth of social workers, speech and occupational therapists and paediatric psychologists. ''For years I trekked here, there and everywhere, in the endless search for experts,'' she says. ''My son had so many tests, he must have thought he was being drafted into the elite moon mission astronaut program.''

She tried everything from cranial massage to ''karma maintenance'' and other areas of scientific expertise based on the kind of medical ideology ''that's been rigorously and methodically proven by Goldie Hawn and other well-known academics''.

''I ricocheted from psychoanalysts to biofeedback practitioners and other nouveau-voodoo nut-jobs, until my own inner-child wanted to throw up.''

So eventually, Lette accepted it and embraced it. And while it was, and still is, a constant challenge, raising a child with Asperger's has taught her many things.

''Jules has taught me humility and patience,'' she says. ''He's taught me to be less judgmental and more accepting. While the endless medical rounds have been financially bankrupting and fighting educational bureaucracy exhausting, life with my deliciously quirky son has also brought me much joy and hilarity. He has enriched my life beyond measure. Professionals, with their oxytocin nasal sprays and neural circuitry rewiring, predict a 'cure' for autism in 50 years or so. But will we then lose our ingenious scientists, virtuosos and innovative artists?''

It's an interesting question to ponder, she says, given the likes of H. G. Wells, Mozart, Albert Einstein, Isaac Newton, Vincent Van Gogh, Andy Warhol, George Orwell, Charles de Gaulle, Thomas Jefferson, Enoch Powell, many famous composers and artists, and even Jane Austen's Mr Darcy, were on the autism spectrum.

''By the way,'' Lette adds, ''I think there are many, many undiagnosed adult males with Asperger's. Especially in Canberra. All those scientists and political analysts. Girls, take note, if your hubby is obsessive about football or trains or numbers, if he's an emotional bonsai - that is, if you have to whack the fertiliser on to get any feelings out of him - if he misreads social situations, there's a good chance he's on the spectrum. Remind you of any politicians we know?''

And speaking of politicians, Lette says it's crucial that governments do all they can to support families dealing with a diagnosis.

''Children on the autism spectrum are complex. And getting help is a postcode lottery. The system is designed with bureaucratic speed bumps to slow down a parent's progress. But one thing is clear: putting a special needs child in a mainstream school is as useless as giving a fish a bath,'' she says.

''Children with Asperger's, well, their disability is invisible. With the onslaught of cutbacks, kids with less severe disabilities, like Asperger's or autism, are losing out in the scramble for funds. Their handicap may be less obvious than those in a wheelchair or wielding a white stick, but they still need and deserve help, and the promise of a life not wasted away in a bedsit living on benefits.''

Julius, now 21, is volunteering with Oxfam and taking a course on radio announcing.

''With his encyclopaedic knowledge of sports, he's Wikipedia with a pulse,'' she says. ''He hopes to become the world's quirkiest sports commentator. With encouragement, love and support, these unique individuals can fulfil their exceptional potential.''

Lette is happy to admit she's always used humour as a survival technique ''to deflect from anything too personal or painful''.

''And parents of special needs children must learn to laugh at life, or you would dive head first into that gin bottle. But it can be annoying when other parents moan on about the fact that their toddlers won't eat broccoli or that their teenagers are giving up Latin or violin lessons. They really have no idea!''

As for Lette herself, she's back in Australia to appear at the Sydney Writers' Festival, on from May 14-20.

''I'm boomeranging back home for the festival,'' she says. ''I adore Australia and pine for home every day. I'm actually trying to get deported. I've decided I'm going to kill a corgi. If I accidentally impale one on the end of my stiletto at the next Buck House Barbie, they're bound to deport me, right?''

Other than that, she's contemplating her next literary venture.

''I'm at that age now where I'm having my own weather, so I think Menopause Blues might be on the cards,'' she says. ''It's so unfair when you think of all the ordeals women go through, starting with period pains, when you're taken hostage once a month by your hormones, followed by pregnancy and childbirth, where you stretch your birth canal the customary five kilometres, followed by mastitis and then the menopause. And then just when everything goes quiet, do you know what happens? You grow a beard.''

A woman can only be serious for so long.

The Boy Who Fell to Earth. Kathy Lette. Random House. $32.95.