For most parents, life with a two-year-old involves hours of chasing a small person around, kicking balls, building towers, man-handling temper tantrums, breezily ignoring food fads and running the gauntlet of potty training. But even if you don’t love your toddler’s terrible twos, you can rest easy, pretty sure that they are on their way to becoming an independent little being.

Life with Lawrence is different. We don’t know whether he will ever learn to crawl or feed himself, let alone walk, talk or live independently. We don’t even know whether he will see adulthood. And we don’t know why.

Lawrence was born healthy but is now what doctors call “complex”. It became clear early on that he wasn’t developing at the same rate as his peers and before we knew it we were on a roller coaster of investigative medical assessments and tests to find a cause.

His brain, heart and kidneys have been scanned. He’s endured chest x-rays, chromosome testing, repeated and inconclusive eye and hearing tests and invasive surgery. And he’s also spent time in the High Dependency Unit for seizures that caused him to stop breathing.

But despite the medical profession’s best efforts, Lawrence’s genetic syndrome remains nameless, categorised only by a very long (and expanding) list of symptoms.

Without a label for his disability, it is impossible to know what Lawrence’s future holds. This uncertainty is frightening but it has also taught us to make hay while the sun shines.

Instead of dreaming of retiring to Cornwall, we recently upped sticks and moved there to a house by the sea. Lawrence likes to copy the sound of the seagulls and on sunny days, he enjoys nothing more than a good splash about in a rock pool.

His presence in our lives has brought those little family moments that can so easily go unnoticed into glorious technicolour. Lawrence managing to sit unaided after a year of daily practice, or his four-year-old sister Beatrice writing her name for the first time are our jump-for-joy moments.

Parenting a child with an undiagnosed syndrome can be tough. There are resources available for children with well-known disabilities like Down’s syndrome or cerebral palsy, and guides for accessing services specific to them. But it is very hard to know where to fit in, when there is no well-trodden path to follow.

With no answers on the horizon, I searched online for families in the same situation. There are rather a lot of us as it happens. In fact, between 30 and 40{af10dd43db2cc98d89795b441eef0c238f898fa1401b2755c0b949d235dc2371} of children with additional needs have a SWAN – syndrome without a name.

I’m now a proud member of SWAN UK, the organisation supporting families with undiagnosed children here in Britain.

While our sons and daughters are all different, there is true strength in numbers and we celebrate the good times as well as supporting each other through the bad. Because we all understand that life is unpredictable with an undiagnosed child.

I am often asked how I manage to remain calm and positive while dealing with such huge uncertainty. The truth is that Lawrence makes it easy. His disabilities may affect every area of his development but his sense of humour button is firmly switched on. He has a divine sense of the ridiculous, he laughs when his sister is getting told off, he likes to “sing” along to 80s power ballads in the car and has a penchant for country music while being a budding percussionist himself. A curry lover and telly addict, in many ways he’s growing up to be a pretty typical bloke.

In spite of his difficulties, top priority for Lawrence is getting on with the business of being a loud, messy, funny, two-year-old boy.

• Katherine Kowalski writes about life with Lawrence on her blog, Orange This Way.

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