The paradox about rare or ‘orphan’ diseases is that, collectively, they are not uncommon. There are thousands of identified rare diseases affecting about 350 million people worldwide. This includes six to eight percent of all Australians, which equates to about 1.2 million people. Yet diagnosis can be difficult, especially if there are perhaps just five other known cases of a particular disease in the world.
“Many parents or patients describe the ‘diagnosis odyssey’ which often involves telling their story over and over to many different clinicians,” explains Dr Tracy Dudding, consultant clinical geneticist at Hunter Genetics. “All they want is a diagnosis yet around 60 percent of individuals with intellectual disability remain undiagnosed while others have a delayed or inaccurate diagnosis.”
Rare diseases share a low prevalence of less than one in 2000. They are serious chronic diseases which are usually life threatening, and are often referred to as ‘health orphans’ because they are neglected with respect to research. About half of these diseases begin in childhood, and about half again involve neurological and intellectual disabilities.
Despite having different diseases, many patients face similar difficulties in their quest for a diagnosis, relevant information and proper direction towards qualified professionals. Dr Dudding says that while there may not be a cure, or even treatment available, a diagnosis is vitally important.
“Once people have a diagnosis they says things like ‘now I know that I didn’t do anything wrong’, ‘we can meet other parents’ and ‘now I have an answer when people ask what is wrong’. The importance of having a name for the disease cannot be underestimated.”
“One of my patients presented with severe intellectual handicap, seizures, brain malformations and incontinence,” she says. “He was also wheel chair bound and, because of overgrowth, weighed 80kg when he was 12 years old. His parents were in financial and emotional crisis because both of them had to give up work to care for their son.”
Families living with rare diseases are often in crisis, but there is some light on the horizon. New high output genetic technology may revolutionise the diagnostic process by outlining a genetic basis for these diseases, and potentially a therapy. Present estimates suggest that 80% of rare diseases may have an underlying genetic basis.
“The International Rare Diseases Research Consortium (IRDiRC ) is also working towards 200 new therapies for rare diseases, and the means to diagnose most rare diseases, by the year 2020,” says Dr Dudding. “But help is also needed now.”
Dr Dudding is a founding board member of Rare Voices Australia which is a not-for-profit organisation established in 2012 to provide a unified voice for all Australians living with a rare disease. The New Zealand Organisation for Rare Disorders (NZORD) was set up in 2000, while orphanet is the reference portal for information on rare diseases and orphan drugs for all audiences.
Without a diagnosis or treatment, patients living with a rare disease, or those caring for someone with a rare disease, can feel like the orphans of the health system. The pivotal role of genetics in the diagnosis, treatment and contribution to the understanding of rare diseases is yet to be realised, but it does give rise to a new era of hope for the millions of people affected by this collectively common plight.