Personalizing Whole Genome Sequencing Doubles Diagnosis of Rare Diseases

In 2018, the UK’s department of health announced an NHS Genomic Medicine Service, which allows patients with rare diseases to have their entire genetic code read in the hope of providing a much-needed diagnosis. However, the interpretation of this data can be extremely challenging and many people with complex, rare genetic diseases still do not receive a molecular answer to the cause of their problems. Now, a new study has found that tailoring the analysis of whole genome sequencing to individual patients could double the diagnostic rates of rare diseases.

In the study, researchers at University College London (UCL, London, UK) sought to offer patients with rare diseases an improved chance of receiving a genetic diagnosis. To do so, they tested how using a genomic medicine team of specialist doctors, bioinformaticians, and scientists could boost the capabilities of NHS diagnostic laboratories beyond the standard semi-automated analysis of data. The UCL team re-evaluated undiagnosed cases to identify clues that might help direct further, more personalized analysis. They subsequently applied additional bioinformatic approaches, using advanced computer technologies to identify genetic alterations in a patients’ DNA which may be causing disease but had been overlooked during routine testing.

Image: Patients with rare diseases now stand an improved chance of receiving a genetic diagnosis (Photo courtesy of Pexels)

The work included 102 undiagnosed patients, suspected of having a primary mitochondrial disease (a large group of incurable genetic disorders that affect children and adults, associated with a broad spectrum of medical problems, severe disabilities, and reduced lifespan), who had undergone whole genome sequencing via the NHS’s 100,000 Genomes Project. This personalized approach increased the diagnostic rate from 16.7% to 31.4%. It also detected potential disease-causing variants in a further 3.9% of patients. Receiving a genetic diagnosis is important as it allows patients to receive access to family planning, specialized IVF, and drugs trials. It can also permit targeted screening of known disease complications and access to drug studies.

“This work is a significant step forward in developing the best ways to maximize the benefits of genome analysis for patients,” said Professor Michael Hanna, Director of UCL Queen Square Institute of Neurology. “It clearly demonstrates that by combining automated approaches to genome analysis with data interpretation by a skilled multidisciplinary team the diagnostic rates doubles. This is an important finding that will influence how genomic medicine diagnostic services should evolve world-wide.”

“The journey to reaching a diagnosis for children and adults with rare, complex, medical conditions can be a very long process, and genomic medicine provides a transformative and powerful tool in helping reach that goal,” said study co-author, Dr. James Davison (Metabolic Medicine Department at Great Ormond Street Hospital and chair of the British Inherited Metabolic Diseases Group) “This study highlights the importance of the collaboration between specialist clinicians and genetic scientists in interpreting the results of genome sequencing to maximize the opportunity of reaching a diagnosis which can then help guide medical management and treatment options.”

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