How monogenic is monogenic? Dravet Syndrome is a severe epileptic encephalopathy starting in the first year of life. More than 80% of patients have mutations or deletions in SCN1A, which makes Dravet Syndrome a relatively homogeneous genetic epilepsy. In addition to SCN1A, other genetic risk factors for Dravet Syndrome have been suggested, and current, large-scale studies including EuroEPINOMICS-RES are studying the genetic basis of the minority of Dravet patients negative for SCN1A. A recent paper in Epilepsia now suggests that a significant fraction of patients with Dravet Syndrome also carry rare variants in SCN9A in addition to the mutations in SCN1A. Is a mutation in SCN1A not sufficient to result in Dravet Syndrome, but needs additional genetic modifiers? Continue reading
Tag Archives: genetic modifier
Exomes to the extreme to identify modifier gene in cystic fibrosis
Monogenic modifiers. Exome sequencing is a well established method to find causative genes in monogenic disorders, with probably more than 100 genes identified through this method in the last two years. In contrast to the ever-expanding list of monogenic diseases solved through massive parallel sequencing, there is widespread skepticism regarding its usefulness in complex genetic disorders. Now, a recent study in Nature Genetics suggests another application for exome sequencing, the identification of modifier genes in monogenic disorders. Continue reading