Institute of Genetics and Cancer

Genetic diagnoses for rare conditions

MRC Human Genetics Unit scientists are involved in a nationwide study to identify genes linked to rare developmental disorders in children: January 2015

Twelve genes linked to rare developmental disorders in children have been identified by a national study that included scientists from the MRC Human Genetics Unit. The nationwide team sequenced DNA and compared the clinical characteristics of more than a thousand children. They found that mutations in the identified genes were responsible for conditions that include intellectual disabilities and congenital heart defects.

Their findings are the first from the Deciphering Developmental Disorders (DDD) project – the world’s largest nationwide programme to sequence genetic material for diagnostic purposes. The DDD project works by collecting clinical and genetic information in a database. If patients who share similar symptoms also have gene mutations in common, it helps to narrow down the search for the genetic causes of their condition.

Scientists worked with 180 doctors from 24 regional genetics services across the UK and the Republic of Ireland. They analysed all of the approximately 20,000 genes in 1133 children with rare developmental diseases and their parents.

This work has demonstrated that genome wide sequencing of an affected child and both parents is the gold standard clinical investigation for children with severe undiagnosed developmental disorders. Identifying a diagnosis in this situation is of great importance both to the family but also to the medical professionals caring for the child.  We hope that this test will become available within the NHS very shortly.

Professor David FitzPatrickJoint Head of Medical and Developmental Genetics at the MRC Human Genetics Unit

The DDD project is led by the Wellcome Trust Sanger Institute in collaboration with the MRC Human Genetics Unit and the Ethox Centre in Oxford alongside NHS colleagues. Professor David FitzPatrick is on the managing committee of the project.

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Fitzgerald TW et al. Large-scale discovery of novel genetic causes of developmental disorders. Nature 2014.

Wright C, et al. Genetic diagnosis of developmental disorders in the DDD study: a scalable analysis of genome-wide research data. The Lancet 2014