Former SAS soldier Andrew Wragg, 38, of Worthing, West Sussex, has been cleared of murdering his son Jacob, 10, who had the rare genetic condition Hunter syndrome.
Jacob Wragg had Hunter syndrome
Q: What is Hunter syndrome?
It is a hereditary disease, which women carry and pass on to their sons, even though they are not affected themselves.
It affects boys because it is an X-linked recessive disease. Females have two X chromosomes, while males have one X and one Y.
So if a boy's X chromosome carries the faulty gene variant linked to the disease on his X chromosome, he will have the condition.
Whereas if a female has one faulty and one normal version of the gene, she will be a carrier of the syndrome, but the functioning version of the gene will mean she will not show any symptoms.
In Hunter syndrome, chemicals called mucopolysaccharide (MPS), found in the matrix which support cells in the body cannot be broken down properly because of the lack of a key enzyme.
The chemicals then build up and can cause organ damage and, in severe cases, early death.
One in 25,000 people are born with some kind of MPS storage disorder, such as Hunter syndrome.
Are all cases the same?
No. There is an early-onset form of the disease, which becomes apparent shortly after the age of two.
It can lead to problems including a large skull, coarse facial features and mental retardation and growth problems.
Hunter syndrome is also linked to an increased risk of heart attack, pressure on the brain and obstructive airway disease.
Children with this form of the disease are expected to die by the age of 20, due to the multiple problems they have.
There is also a late-onset form of Hunter syndrome which develops later in life and has less severe symptoms. People with this form of the condition can live until they are 60.
Is there a cure?
No. Doctors can currently only offer physiotherapy, hearing aids, or other treatments to relieve symptoms.