Newbury mum’s ‘relief’ after research study diagnoses daughter’s disability

A Newbury mother-of-three has expressed her “massive relief” after discovering her daughter’s severe learning disability was not inherited.

Fifty-four-year-old mum, Tracy Mann, spoke out on Rare Diseases Day today (February 29) about the importance of researching and supporting people with rare diseases.

Her daughter, Tiffany, aged 24, has global developmental delay, a severe learning disability impacting her movement, speech and social development.

But after taking part in the Deciphering Developmental Disorders (DDD) study, Mrs Mann discovered that a mutation in the MEF2C gene caused her daughter’s disability — not a genetic mutation passed down from her or her husband.

“When I finally got that letter with a diagnosis, I must admit I had a few tears,” she said.

“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.”

Miss Mann was diagnosed with global developmental delay in 2001 following testing, aged 18 months.

Mrs Mann, who is her full-time carer, continued: “At eight-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.

“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; deformities such as cleft lip, extra fingers or toes; and problems with learning and behaviour.

Studies like the DDD aim to understand 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.

Many are due to errors in a person’s genetic makeup.

Some will have come from one or both parents, while others will have occurred for the first time in the patient’s DNA.

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

Mrs Mann added: “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.”

Miss Mann joined the trial at Dingley Child Development Centre, Reading, and was tested for several rare diseases, which came back negative.

In 2021, she 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.

Mrs Mann 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.

The DDD 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.