Jumping genes linked to development disorders

Monday October 14th, 2019

Jumping genes are behind the genetic changes in some patients with undiagnosed neurodevelopmental diseases, according to a new study.

The largest study of its kind into childhood developmental disorders from the Wellcome Sanger Institute, Cambridge, UK, and partners in the NHS Regional Genetics services has resulted in genetic diagnoses for three children with previously undiagnosed rare developmental diseases.

The researchers believe the diagnoses for the youngsters, all of whom were enrolled in the Deciphering Developmental Disorders (DDD) project, will help the families access support and understand the disease risks for any future children.

In this study, the researchers studied the genomes of nearly 10,000 children enrolled in the project, was launched in 2010 to provide genetic diagnoses for the families of children with severe undiagnosed developmental disorders, looking for jumping genes that were not present in the parents.

Their findings are published in Nature Communications.

Transposons, known as jumping genes, are pieces of DNA that can jump around in the genome. Sometimes they land in the middle of genes and stop them working, but it not been known how often transposons lead to rare developmental disorders.

The research team found that the transposons were likely to be the cause of the developmental disorder in three previously undiagnosed patients because they had jumped into different genes in each patient, preventing them functioning properly. The study also showed a transposon in a fourth patient who had been diagnosed previously.

First author Dr Eugene Gardner, of the Wellcome Sanger Institute, said: “This is the first time we have been able to estimate the contribution of jumping genes, known as transposons, in a large sequencing cohort of rare developmental disorders.

“We found that transposons were the likely cause of the symptoms of four of the 9,738 patients, three of whom had not had previous diagnoses. These are significant diagnoses for the families involved, and this study is another step along the path to understanding the causes of developmental disorders.”

The team developed and validated analytical pathway that could quickly assess patient genomes at scale, looking for transposon-created variants. This software is now openly available for academic use and could be used to help diagnose rare transposon events in future patients.

Eugene Gardner et al. Contribution of retrotransposition to developmental disorders. Nature Communications 11 October 2019; doi: 10.1038/s41467-019-12520-y.

Tags: Child Health | Genetics | UK News

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