By the time recruitment to DDD finished we had recruited over 13,600 patients. This was an amazing surpassing of our 12,000 target, and thus we applied for a budget extension to enable us to sequence EVERY CHILD in DDD as well as ALL COMPLETE FAMILY TRIOS (Mum, Dad and child). The necessary additional funding has allowed us to complete exome sequencing of ~33,000 DDD individuals. We have worked hard to analyse this enormous amount of data and resumed reporting back plausible diagnoses to clinical teams last autumn.
The number of known developmental disorder genes upon which we focus our initial attentions has now increased to 1,400. If you want to know more about a specific gene try looking at our genotype-to-phenotype online database!
The DDD study team has discovered 30 more genes not previously associated with developmental disorders (see table) and we estimate that these account for ~5% of diagnoses in DDD. Work on DDD data by NHS doctors focussing on specific genes and conditions has also led to new gene discoveries. With additional information taken from the wider scientific community, as well as our continued analysis of ALL genes in all DDD families, we are constantly adding to the list of genes known to cause developmental disorders. This iterative process will enable us to make even more diagnoses in the future. See this link for the growing list of DDD publications.
Despite this progress, we expect that around half the families in DDD will not get a diagnosis from this first phase of the study. However, due to recent reductions in the cost of DNA sequencing, as well as securing additional funding, we are implementing other experimental strategies and analyses to find as many diagnoses as possible until at least 2021!
Thank-you for your continued patience and support while we continue to work with your data in the years ahead!https://www.ddduk.org/updates.html