Discovering our children have a rare genetic mutation has opened new doors for the future

Dixon family having fun on a giant swing
Dixon family having fun on a giant swing

Mel & Charlie have three children, Tom, Harry and Rosie. When they were born, both Tom and Rosie didn’t learn to speak quite as quickly as their friends, and both were diagnosed with mild learning difficulties and Dyspraxia, which affects their co-ordination, when they were at primary school.

“I started to notice that they were a little shaky, but I thought it was part of the dyspraxia. However, when Tom was about seven, it was getting more noticeable so we got referred to a neurologist.”

The family met multiple neurologists but no cause for the tremors, motor skill and learning difficulties were discovered so they decided to go to a private genetic clinic which screened for a range of relatively common genetic conditions.

“The tests came back negative which was good, but on the other hand we still had no answers.”

It was then that Mel & Charlie came under the care of the Clinical Geneticist at St. George’s Hospital in London. Dr Elmslie suggested that they might consider getting Tom & Rosie’s genome sequenced by a process called Whole Genome Sequencing which can detect changes in your genetic make up. This is offered by the NHS Genomics Service.

Whole Genome Sequencing identified that both Tom & Rosie have the same ultra rare DHDDS gene mutation. These mutations cause symptoms such as learning difficulties, tremors, myoclonus and seizures all of which can range from mild to severe.

As the DHDDS gene was only decided to be pathogenic in 2021, very little is known about it and so treatment is largely symptomatic. However, this new knowledge has opened doors for the family and they now hope to find a treatment that can treat the cause of the disease rather than just managing the symptoms.

We have focused our energy on giving our children the brightest future possible

The Dixons, supported by family and friends, have set up the charity Cure DHDDS and are working hard to inspire and stimulate research amongst the scientific community to understand more about what this genetic change means and how it can be treated.“Right now, very little is known about DHDDS. There is no treatment, so our focus is on encouraging Doctors and researchers to unlock the mysteries around our condition. Symptoms have shown to progress in many patients, so we are fighting against time to give our children and all those suffering with these mutations the brightest future possible.”

The genetic testing and subsequent diagnosis, although extremely difficult, has given the family a focus. They have already created a Facebook group to connect with other people who have a DHDDS diagnosis. They are also working with a range of medical professionals from across the world with the aim of starting active research into the gene and screening for potential treatments.

To learn more about DHDDS and get involved, visit

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With any Whole Genome Sequencing (WGS) test ordered, a Record of Discussion (RoD) form will also need to be submitted. This document is to record the patient’s consent for genomic testing and their choice on taking part in research. Guidance on the patient choice conversation can be found here
This RoD form will be available for clinicians to download from this webpage. Once completed with the patient, it can be send to the lab with the corresponding test order form and sample.
Tests available to order will be listed in the National Genomic Test Directory. A test order form will soon be made available for clinicians on this webpage to download and complete. This form will include the address of the laboratory that the appropriate sample and completed form needs to be sent to.
Until the new Genomic Laboratory Service goes live, please continue to follow existing test order processes.
Later this year, the online test ordering tool for Whole Genome Sequencing will be integrated into the National Genomics Informatics System (NGIS) and clinicians will be able to search or filter to find a clinical indication, confirm eligibility criteria and start the test request process for their patient.