A microscopic look at the 16p13.11 microdeletion

The patchwork chromosome. The human genome is a puzzle of duplications, duplications-within-duplications and more complex rearrangements.. Some of these duplications can misalign at meiosis and generate microdeletions and microduplications. The duplication architecture of the human genome is more pronounced in some chromosomes than in others. Chromosomes 15 and 16 are particularly rich in duplications, which is the reason several syndrome-associated microdeletions and microduplications are found there. One of these microdeletions is the 16p13.11 microdeletion. As a recent paper has looked as histological findings in brain tissue of patients with these deletions, it is time to review the only established genetic risk factor that contributes to wide range of epilepsy syndromes. Continue reading

Exome study in IGE questions channelopathy concept

IGE and the hunt for rare variants. Idiopathic Generalized Epilepsy (IGE) or Genetic Generalized Epilepsy (GGE) is one of the most common epilepsy subtypes. Family studies and twin studies suggest that genetic factors play an important role. Some families with mutations in GABRG2, GABRA1 and EFHC1 are known, and recurrent microdeletions are found in 3% of sporadic patients. For the majority of patients, the genetic basis remains unknown, but a heterogeneous pattern of rare variants is expected. Much effort is currently spent on genetic studies in IGE including the EuroEPINOMICS CoGIE study. A recent paper now reports the first exome sequencing in IGE to identify rare variants…

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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