Ava Walden, from Southend was diagnosed with a SWAN - aka syndrome without a name - by doctors who could not identify her genetic condition.
The condition means she is non-verbal, has eczema that “looks like burn marks”, and respiratory issues which mean she cannot cough.
Ava is also blind and her respiratory issues mean even a common cold could be life-threatening.
Mum Claire Walden, 38, spoke about the difficulties she faces daily ahead of a major fundraising event.
Claire said: “We’ve had a few scary situations and nearly lost her, but she is a happy little girl who works hard.
“She’s six but her mental age is between two years and 18 months with global development delay.
“I’ve been to a few conferences this year to find tools which will make her quality of life better that aren’t available locally.
“She needs things like an adapted vehicle, a comfortable chair at home, an accessible wheelchair for beach days, and equipment for an Eyegaze machine.”
Ava’s inability to cough means she cannot clear out secretions which build up and clog her lungs.
She has a weak chest and is on a ventilator at home to help her breathe when sleeping.
Her first ordeal with sepsis meant she was on a ventilator for seven weeks, and she has been on life support several times since then - including during a recent family holiday to Spain.
Claire added: “Last year we went away for holiday for the first time in a long time.
“We were only there for four hours before she had to go to hospital on life support.
“Not long after we were repatriated to the UK.”
Claire is organising a charity ball for Ava in Stock Brook Manor, Billericay, in October.
Funds raised will go towards the unique equipment required for Ava to have an improved daily experience.
Claire added: “Some things aren’t provided locally. We’ve tried but you come up against people that tick boxes and don’t really advocate.”