From 6 million to 1
Jessica was one of the first children to receive a diagnosis of her rare condition from the 100,000 Genomes Project. Her diagnosis means a treatment could be recommended too. She, together with each of her parents, donated a small sample of blood at Great Ormond Street Hospital and their genomes were sequenced.
Bioinfomaticians analysed Jessica’s genome sequence to find the cause of her condition. Read on for how it worked.
Analysing Jessica's genome
Jessica's genome was compared to the reference human genome sequence to find differences, called variants, and then further research was done to narrow it down
Finding an answer using PanelApp
Researchers checked Jessica’s variants against a knowledge base curated by Genomics England – called the PanelApp – to ultimately get her diagnosis.
PanelApp is a crowdsourcing tool for the rare disease genetics community, which has information on thousands of genes that may be linked to rare diseases, as reported by expert doctors and researchers.
By using the gene panels in the app, researchers were able to find one variant as being linked to symptoms similar to Jessica’s. The name of this gene is SLC2A1.
How does this explain Jessica’s symptoms?
In Jessica’s genome, there is a deletion in one copy of her SLC2A1 gene. The deletion means that the protein can’t be made at all from that copy of the gene, so she doesn’t have enough in her body.
The SLC2A1 gene makes a protein that transports a certain type of sugar into the brain. Two healthy copies of this gene are needed for this protein to transport enough of this sugar to fuel the brain. Mistakes in the SLC2A1 gene can cause ‘Glut1 deficiency syndrome’ – which is Jessica’s diagnosis.
Glut1 deficiency syndrome affects only about 500 people worldwide.
Treatment for Glut1 deficiency syndrome
Research has shown that in some patients who have Glut1 deficiency syndrome, a special low-carbohydrate diet can help reduce the number of seizures they experience. This ‘ketogenic diet’ provides an alternative energy source for the brain.
The ketogenic diet will be carefully tailored for any individual patient, and should only be used under the care of medical professionals.
It’s not always so straightforward
Jessica had a very positive outcome. For some families, researchers won’t be able to clearly identify the cause of disease right away. For these families, experts in our research partnerships continue looking for the cause.
Even when a cause can be identified easily, this knowledge won’t always suggest an immediate treatment or come in time to change patient care. However, identifying the cause can bring peace of mind, help unite families affected by similar genetic conditions, and inform family planning decisions.
Anyone who takes part in our initiatives or studies will be helping others in the future with the same condition.
Support for rare disease patients
Each of these charities or support organisations can provide information, support or services for families affected by rare diseases.
Genetic Alliance UK is the national charity working to improve the lives of patients and families affected by all types of genetic conditions.
Gene People UK is a genetic conditions support network with information for affected families.
Contact A Family is a national charity for families with disabled children.
EURODIS, Rare Diseases Europe, is a patient-driven alliance of patient organisations representing 695 rare disease patient organisations in 63 countries.
Rare Disease UK is the national alliance for people with rare diseases and all who support them.
SWAN, Syndromes Without A Name UK offers support and information to parents of children with undiagnosed genetic conditions.
Unique, Understanding chromosome disorders aim to inform, support and alleviate the isolation of anyone affected by a rare chromosome disorder and to raise public awareness.
MyGene2 allows families to search for and contact other families who have the same condition or mutations in the same gene in order to share information and offer support.
RareConnect is a safe, easy to use platform where rare disease patients, families and patient organizations can develop online communities.
For support with a specific rare disease, you can search for patient organisations and charities on the Rare Disease UK website.