Lauren, along with her parents David and Lee, signed up at Guy’s and St Thomas’ to the 100,000 Genomes Project. The national project was set up in 2013 by Genomics England and involved sequencing 100,000 genomes from people who have a rare disease or cancer. Your genome is your body’s instruction manual. It is made up of DNA and there is a copy in almost every cell.

Sequencing of Lauren’s genome and further research revealed that she has CDG – Congenital Disorders of Glycosylation – a large group of rare inherited diseases affecting glycosylation.

Glycosylation is the process of adding sugar building blocks (also called glycans) to proteins. Every part of the body requires glycosylation to work normally, which explains the many different health problems that affect people with CDG.

Lauren said: “I feel like I belong somewhere now and I’ve been able to talk to people with the same condition. It’s something I’d always wanted to know and I hope other people who don’t yet have a diagnosis for their condition don’t give up hope.”

Although the diagnosis won’t change Lauren’s treatment options, it has given her family peace of mind after spending so many years wondering.

Her mum, Lee, said: “We broke down in tears when we finally got the result because it was a huge sense of relief for Lauren and the whole family. We had always been desperate to know, mainly because knowledge helps with making decisions. Once she got the diagnosis she was able to be referred to more clinical teams who are working together and doing their best for her – we don’t feel on our own.”

Lauren’s dad, David, added: “The diagnosis gave us a sigh of relief having spent 25 years in the wilderness. We’ve spent a lot of Lauren’s life wondering what to do when another medical problem occurs, but now we’re able to look it up and join online talks about CDG and be reassured.”

Dr Rachel Jones, a consultant in clinical genetics and clinical scientist at Guy’s and St Thomas’, said: “I was delighted to finally be able to give Lauren an answer for why she has the problems she does, after years of genetic testing as well as many other diagnostic investigations. While there isn’t currently a treatment targeted specifically for Lauren’s condition, it still provides information about her future as well as an explanation for what has happened in the past.

“We know that many people with genetic conditions which have remained a mystery for some time find having a name for their condition very empowering. The introduction of whole genome sequencing means we will be able to help many more families find their diagnosis, without waiting as long as Lauren.”

Dr Jones added: “Initial analysis of Lauren’s 100,000 Genomes Project data did not reveal her diagnosis, and it was further research into this using information from other members of her care team that enabled me to find it. This discovery will help other people in the project and, going forwards, other people having their genome sequenced in the NHS will receive a much more timely diagnosis.”

NHS England and NHS Improvement has introduced the NHS Genomic Medicine Service (GMS) to provide equitable access to genomic testing for patients. The NHS GMS is delivered through a network of seven NHS Genomic Laboratory Hubs and supported by seven NHS GMS Alliances across England. They are responsible for the embedding of genomics into mainstream clinical care so that more people, like Lauren, can potentially receive a faster diagnosis and even a potential treatment.

Professor Dame Sue Hill, Chief Scientific Officer for England and Senior Responsible Officer for Genomics in the NHS, said: “I am delighted with the outcome for Lauren and her family and this is exactly what the NHS Genomic Medicine Service is aiming to do – to embed genomics in patient pathways to deliver faster diagnoses, more effective treatments and deliver truly personalised care for our patients.”

The South East NHS Genomic Laboratory Hub is led by Guy’s and St Thomas’ NHS Foundation Trust, providing genetic and genomic testing for patients in NHS trusts in south London, Kent, Surrey and Sussex.

Dr Richard Scott, Chief Medical Officer of Genomics England, said: “Improved knowledge of genomics and the whole genome sequencing and data infrastructure that the government and NHS have invested in now offers us the ability to radically transform diagnosis, as this family’s story shows. We’re proud at Genomics England to be working in partnership with the NHS to bring the benefits of whole genome sequencing to patients.”