They had a fairytale American childhood - but was radiation slowly killing them?
After Kim Visintine put her son to bed every night at a hospital in St Louis, Missouri, she spent her evening in the hospital’s library. She was determined to know how her boy had become seriously ill with a rare brain tumour at just a week old.
"Doctors were shocked," she says. "We were told that his illness was one in a million. Other parents were learning to change diapers but I was learning how to change chemotherapy ports and IVs."
Kim’s son Zack was diagnosed with a glioblastoma multiforme. It is a brain tumour that is very rare in children and is usually seen in adults over 45.
Zack had chemotherapy treatments but doctors said there was no hope of him ever recovering. He died at just six years old.