More than £35,000 has been raised after the death of a two-year-old Lancaster girl just three years after her brother died of the same rare condition.
Isabelle Cooper, who had PPA2 deficiency which can lead to sudden cardiac arrest in infants and young people, died on Thursday.
Her brother Alexander, three, died in 2021.
Their parents Emily and Darren discovered two years later that he died from a genetic abnormality called a PPA2 mutation, and that Isabelle had inherited the gene too.
They have been campaigning for better awareness of sudden childhood death and the PPA2 deficiency.
Emily, posting on X, said: "We are devastated to say that our beautiful Isabelle died in the early hours of this morning.
"We are absolutely broken. However, we want you all not to think of her death, but to honour her by living life as she did: fearlessly, joyously and spontaneously.
"Thanks so much for all the condolences for the loss of Isabelle.
"We're so grateful for offers of help but as we can't think straight at the moment, a colleague has kindly done a fundraiser page until we can function enough to know what we need.
"Our beauty, our sunshine in the darkest times. You spent so many happy times loving our new garden. Our new house is so empty without your beautiful thudding feet and constant chatter and giggles. I can't bear your empty bedroom, finished only a month ago. I'm just so lost.
"We don't have the strength right now to reply to you all, but please know how grateful we are for the love and kindness you are showing us. We are bereft, missing the soul of this house who made us all a little sillier and fun."

Emily is a senior lecturer in the University of Central Lancashire school of law and policing.
There has been an outpouring of support for the family and an online fundraising page, which was set up by Emily's colleagues and friends, has raised £35,753 at time of writing.
The page says: "It is truly heartbreaking to share that Emily and her family have suffered another devastating loss with the passing of their two-year-old daughter, Isabelle.
"Isabelle had PPA2 deficiency, which can lead to sudden cardiac death in infants and young people.
"Emily also lost her three-year-old son Alexander to this in 2021. She has undertaken some amazing work around raising awareness of this condition and SUDC (Sudden Unexplained Death in Childhood) generally, using her skills and lived experience to help others.
Alexander is pictured below.

"Emily is such a loved and valued colleague and friend and we'd like to help her and her family now by offering a bit of support during this time. Anything you can donate would be much appreciated and will be used to pay for essentials such as meals, help with household necessities and Isabelle's funeral.
"The family also need to go through the process of replacing Alexander's headstone for one which includes Isabelle too. All of this is really incomprehensible, so any help will go a long way.
"As a school and wider community we have pulled together before in times of need and hopefully you are able to donate something to ease the burden Emily and her family are now facing. Please also share this with others as we want to be able to offer as much support as possible."
The fundraising page can be found HERE.


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