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Berkshire mum’s “relief” after research study diagnoses daughter’s disability

A Berkshire mother-of-three has spoken of her “massive relief” to find out that her daughter’s severe learning disability was not inherited from her parents, after taking part in a research study.

Newbury’s Tracy Mann, 54, spoke ahead of Rare Diseases Day, which takes place on February 29, to raise awareness of how people with rare diseases can be supported and the importance of taking part in research.

Tracy’s daughter Tiffany, 24, has global developmental delay, a severe learning disability that causes problems with movement, speech and social development.

Through taking part in the Deciphering Developmental Disorders (DDD) study, it was discovered that a mutation in the MEF2C gene caused Tiffany’s disability, not a genetic mutation passed down from her parents.

Tracy said: “When I finally got that letter with a diagnosis, I must admit I had a few tears. I’d waited so long and it was a massive relief to find out that Tiff’s gene mutation was random and hadn’t come from either mine or her dad’s DNA.

“As a parent of a child with a severe condition, you do worry that you might have done something wrong.”

The Deciphering Developmental Disorders study is jointly funded by the Health Innovation Challenge Fund and the Wellcome Sanger Institute and is supported by the National Institute for Health and Care Research.

Tracy, who is Tiffany’s full-time carer, said: “At 8 months old I noticed she wasn’t reaching her milestones. I picked up on it pretty quickly as I’ve got two older sons who didn’t have any delays in their development.”

Following testing, Tiffany was diagnosed with global developmental delay in 2001 aged 18 months.

Tracy said: “It was a huge punch to the stomach when Tiff was diagnosed. I had friends with children the same age and it was hard to watch the differences between my child and theirs get bigger and bigger.”

Some of the most common developmental disorders involve:

  • Problems with growth of the body or specific parts of the body, such as an unusually sized head
  • Deformities such as cleft lip, extra fingers or toes
  • Problems with learning and behaviour

Studies like the DDD study are trying to understand what causes these developmental disorders. Many are due to errors in a person’s genetic makeup. Some will have come from one or both parents and some have occurred for the first time in the patient’s DNA.

The DDD study aims to find out if the use of genetic technologies can find out the causes of developmental disorders and give parents of people with rare diseases a reason as to why their child’s development has not followed the usual pattern.

The study asks participants to provide saliva and blood samples to search for genetic and chromosome abnormalities in the patient’s cells. Samples are also compared at laboratories against thousands of other participant samples at once to search quickly for similarities in the gene mutation.

Parents of the participants were also asked to provide a saliva sample to exclude the analysis of benign genetic changes that have been inherited from the parents and generate faster results.

With Tracy’s permission, images taken by NHS staff to monitor Tiffany’s physical development were shared with other genetics speciality doctors in the UK.

Tracy said: “Tiff has a tuft of hair on her neck, which some of the doctors had seen before in other undiagnosed children. The doctor suggested the DDD study to see if we could get some more insight into her condition and what may have caused her developmental delay.”

Tiffany joined the trial at Dingley Child Development Centre, Reading, part of Royal Berkshire NHS Foundation Trust, and was tested for several rare diseases, which came back negative.

In 2021 Tiffany was finally given a diagnosis of MEF2C-related developmental delay, which is caused by a mutation in the MEF2C gene. There is no treatment and care is individualised for each patient.

Tracy said: “I’m eternally grateful for the testing Tiff had as part of the study. Without it my family would never have got the answers we did.

“I would recommend anyone to take part in research if they are asked to volunteer. At the end of the day, if it helps other people or families, it’s a good thing. In our case, the study ran quietly in the background and didn’t interfere with our lives in any way.”

Last year the study reported it had provided diagnoses for about 5,500 children, including 60 new conditions discovered by the study. Around three-quarters were not inherited from either parent. For more information about the study visit

The University of Oxford’s Prof Usha Kini, who is leading the study in the Thames Valley, said:  “Finding the genetic diagnosis not only provides families with an explanation for their relatives’ problems, but also allows doctors to individualise the management plan for patients and often predict the long-term outcome. It also opens doors for genetic testing for other family members who may be at risk of inheriting or passing on the disorder.” 

Participating in health research helps develop new treatments, improve the NHS, public health and social care and save lives.

The NHS, public health and social care supports research by giving patients opportunities to take part in trials. Healthy people can also take part so results can be compared to those with a medical condition.

Patients are also encouraged to ask their doctor or health professional about research opportunities and search for trials seeking volunteers.