Rare disease diagnosis improved by whole genome sequencing

Whole genome sequencing of NHS patients with rare diseases can provide diagnoses that could lead to more personalised care or treatment and potentially save the NHS money, a study has shown.

In 2012, the 100,000 Genomes Project set out to sequence thousands of genomes from NHS patients with rare genetic diseases or cancer. It was believed the project would revolutionise the way people were diagnosed and cared for and establish personalised treatment options. A recent pilot study, published in the New England Journal of Medicine, analysed genomes from 4660 people, from 2183 families, who took part in the 100,000 Genomes Project.

Professor John Sayer, from the University of Newcastle, who led recruitment for the North East said: 'Our study is a world-first confirming a definitive genetic diagnosis can vitally help patients and their families, giving them access to specific information about prognosis, treatment, genetic counselling and reproductive options'.

Led by Genomics England, the collaborative study found that whole genome sequencing led to a new a diagnosis for 25 percent of the participants. Of these participants, 25 percent were then able to access information and treatments that were potentially beneficial. Just 0.2 percent of the diagnosis made were described as having no benefit.

The number of people who received a genetic diagnosis varied significantly based on the type of disease they had. The diagnostic success rate was as high as 40-55 percent in participants with intellectual disability, vision and hearing disorders and as low as six percent for participants with family cancer syndromes.

The study is the first to investigate the diagnostic and therapeutic importance of whole genome sequencing in a national healthcare system, thereby supporting its inclusion in medical systems around the world.

In a case which typified the value of whole genome sequencing in healthcare, genomic analysis of a baby boy who died aged four months found that his health problems were caused by a genetic variant that caused the faulty transport of vitamin B12 into his cells, the Guardian reported. By identifying the underlying cause of death, doctors were able to test his younger brother at birth and subsequently establish a programme of weekly vitamin B12 injections which halted his disease progression.

Professor Darren Griffin, professor of genetics at the University of Kent who was not involved in the research, said 'this study is undoubtedly good news for healthcare and for the NHS. The ability to diagnose rare diseases early is the key to successful treatment and, as whole sequencing technology gets cheaper and cheaper, its widespread roll out is becoming inevitable.'