While many patients can wait eight years or longer for a diagnosis, experts say that one single genetic test can identify a rare disease 14 hours after a child’s birth – and yet while this technology exists, more buy-in is vital before it becomes a reality for South Africans.
Thousands of patients will live with a rare disease for years before it is diagnosed, reports News24. Just as many spend the rest of their lives without treatment and answers.
Professor Shahida Moosa, head of the rare disease genomics research group at Stellenbosch University’s Faculty of Medicine and Health Sciences, said for many patients, access to genetic testing and diagnosis depends largely on where they were born and into what circumstances.
There are more than 7 000 rare diseases, and most (around 80%) can be detected with genetic testing.
Kelly du Plessis, founder and CEO of non-profit organisation Rare Diseases South Africa (RDSA), said about 4.1m people in SA live with a rare disease.
“However, the diagnostic rate remains low, for various reasons,” she said. “These include lack of awareness, limited local diagnostic availability, the cost of overseas testing and lack of suitable referral systems for those needing to access expertise.”
Moosa said the under-diagnosis was a “dire situation” worldwide because these were not prioritised by governments.
“The length of time until you are diagnosed – what we call the diagnosis odyssey – depends on where you’re born and what access you have to healthcare. In a well-resourced country, it could be seven to eight years. If you live in Delft or Khayelitsha, it could be your whole life,” she said.
A diagnosis was essential to ensure patients can access treatment, said Du Plessis, and critical for some diseases. For example, patients with congenital hypothyroidism could lose an IQ point for every week they are not diagnosed.
“Often in South Africa, patients are diagnosed so late they have limited prospects of successful treatment.”
Genomic sequencing remains one of the most effective tools in diagnosing rare diseases, a disease found in one in every 2 000 births. Genetic testing looks for mutations in the patient’s DNA – what Moosa calls the “spelling mistakes” in the instruction manual of each individual.
After extracting DNA samples from blood or saliva, a researcher must analyse a large amount of data to find the one mutation causing the rare disease.
Moosa said advances in the field were rapidly evolving.
Recently, a team at the Rady Children's Institute for Genomic Medicine in California developed an ultra-rapid sequencing process to diagnose rare diseases in under 14 hours.
It takes the local teams longer than this to produce results, but with the correct support, Moosa believes local genetic testing could have the same transformative effects.
“We have the infrastructure and technology, and we’re training people to do the analysis faster. But we need support from the Department of Health and other role-players.
“Being able to run genetic testing so quickly would be transformative. Diagnosis in the first few days of life can prevent brain damage and situations where children are unable to speak or walk. It can save lives and quality of life, and help us to plan for the future and ensure patients have the right medication and treatment.”
Although genetic testing costs between R7 000 and R10 000 per patient, it can save the healthcare system thousands of rands in admissions and testing, said Moosa, whose work is largely funded by the Early Investigators’ Programme of the South African
Medical Research Council.
“We need buy-in at all levels, from government, the Health Department, healthcare workers, and communities,” she emphasised.
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