Finally Diagnosed: The DDD Study is Getting People Answers

Growing up without a diagnosis is hard. In a world which frequents new scientific discoveries, you’re still living as a medical mystery. When no one knows the answer, patients often don’t receive the type of treatment they need. Since doctors don’t know the root cause of their problems, all they can do is treat the symptoms.

The DDD study is trying to get more people answers.

The DDD Study

Most rare conditions occur as a result of genetics. DNA is a complicated structure, and there are practically an infinite number of ways it can produce an error. This is what makes diagnosis so difficult for many rare disease patients. Some rare diseases like cystic fibrosis affect thousands of people, while others have only one known case and every single week 5 new rare diseases are documented.

The  Deciphering Developmental Disorders (DDD) study began 8 years ago with a goal to give more people a proper diagnosis. Since its start, they have tried to find diagnostic answers for 13,600 children who’s condition is perceived to be of genetic origin.

In its initial round, the study was successful in finding a diagnosis for approximately 1/3 of patients. But researchers didn’t give up on the other participants. Three years later the study was conducted again, and the diagnostic rate went up to 40%. Why such an increase? Because we’re constantly learning more about the human body and the genes that comprise it. As new genes are discovered, were able to analyze their normal state, and what might be an illness-causing mutation.

The study is expected to run until 2021, and is committed to finding answers for as many children as possible. The dream of course, is to find a diagnosis for every participant.

Alix and Pip’s story

Alix and Pip are twins. Their parents were told they had some sort of developmental delay. So throughout their childhood they joined different support groups for children and families with similar conditions and tried to manage their symptoms the best they could. But their mother found they never fit quite right with any of the groups they joined. Her children experienced different things than the other children.

After 10 years of living with only vague answers, the twins, per recommendation of their pediatrician, joined the DDD study to see if their condition could be of genetic origin. They sent in their saliva samples and then went on with their lives. Eventually the study slipped from their minds.

But four years later they got a letter in the mail. The twins had a diagnosis.

Alix and Pip were told they had the DDX3X mutation. With this newfound knowledge they joined the DDX3X Foundation. While there are currently only 250 documented cases of this condition, the family immediately had so many more answers, and so much more support.


A DDX3X mutation can impair a child’s ability to process visual information. Prior to diagnosis, it was believed that Alix and Pip simply had poor vision. Learning that they could see, just had trouble processing, explained why it was more difficult for the children to learn shapes in school.

Similarly, the twin’s family learned that constipation often comes with a DDX3X diagnosis. It turned out that the potty training issues the family had were due to the fact that the girl’s muscles within the gut don’t work properly. With this new information, they were able to receive the proper treatment they needed to resolve the issue.

The twin’s mother says, “I really think that the twins would be very much side-lined without their diagnosis. I really don’t think we would have moved forwards on many of the issues that they have without a diagnosis.”

The future of DDD

As the study has progressed, researchers have faced challenges. For instance, when they come across genetic information they weren’t looking for (such as a mutation which increases the patient’s risk for cancer), do they still share it with the participants? As a result of this dilemma, along the way they have had to conduct separate studies to navigate these ethical questions.

You can read more about the studies conducted by their ethics team here.

But despite these setbacks, as of 2018, the DDD study has published 125 researchers papers and documented 49 new genetic conditions.

Its important to note that for some of these newly diagnosed individuals (depending on their current treatment) not much actually changes in terms of their medical care. But for even those individuals, a diagnosis can still bring peace of mind and a better quality of life simply because it eliminates the guessing game, finally giving them a reason for their experiences. It also provides researchers more information for the rarest of conditions, which will hopefully lead to more treatment options in the future for these individuals.

You can read more about the DDD study as well as Alix and Pip’s full story here.

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