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Case study: Taking part in genetics research: Tiffany’s story

Researchers were able to explain why Tiffany Mann has global developmental delay, a severe learning disability, thanks to her involvement in a study.

Through taking part in the Deciphering Developmental Disorders (DDD) study, it was discovered that a mutation in the MEF2C gene caused 24-year-old Tiffany’s disability, which causes problems with movement, speech and social development, not a genetic mutation passed down from her parents.

Mum Tracy, 54, of Newbury, Berkshire, 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.”

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.”

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.

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.”

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

Talk to your healthcare professional about taking part in research or search for studies seeking volunteers at Be Part of Research.