Dravet syndrome is a severe epilepsy syndrome characterized by infantile onset of therapy-resistant, fever-sensitive seizures followed by cognitive decline. Mutations in SCN1A explain about 75% of cases with Dravet syndrome; 90% of these mutations arise de novo. We studied a cohort of nine Dravet-syndrome-affected individuals without an SCN1A mutation (these included some atypical cases with onset at up to 2 years of age) by using whole-exome sequencing in proband-parent trios. In two individuals, we identified a de novo loss-of-function mutation in CHD2 (encoding chromodomain helicase DNA binding protein 2). A third CHD2 mutation was identified in an epileptic proband of a second (stage 2) cohort. All three individuals with a CHD2 mutation had intellectual disability and fever-sensitive generalized seizures, as well as prominent myoclonic seizures starting in the second year of life or later. To explore the functional relevance of CHD2 haploinsufficiency in an in vivo model system, we knocked down chd2 in zebrafish by using targeted morpholino antisense oligomers. chd2-knockdown larvae exhibited altered locomotor activity, and the epileptic nature of this seizure-like behavior was confirmed by field-potential recordings that revealed epileptiform discharges similar to seizures in affected persons. Both altered locomotor activity and epileptiform discharges were absent in appropriate control larvae. Our study provides evidence that de novo loss-of-function mutations in CHD2 are a cause of epileptic encephalopathy with generalized seizures.

No abstract

No abstract

Aims: In the current study we aimed to explore the prevalence of gastrointestinal (GI) manifestations in hereditary transthyretin amyloid (hATTR) amyloidosis associated with Glu89Gln mutation. Methods: We recruited 78 patients with hATTR amyloidosis associated with Glu89Gln mutation. The diagnosis of hATTR was defined by a documented transthyretin mutation through DNA analysis. Symptoms were recorded as present or absent at the time of enrollment into the study. The gastrointestinal (GI) symptoms checklist included the following items: early satiety, nausea, vomiting, constipation, alternating diarrhea/ constipation, diarrhea, fecal incontinence and unintentional weight loss. Results: Forty-two patients (53.8%) reported at least one GI symptom or sign. Diarrhea was the most frequently reported (30.8%), followed by unintentional weight loss (28.2%) and nausea (21.8%). Fecal incontinence (3.8%) was the least common one. No significant gender related difference in overall GI symptom prevalence was found (females 52.16%, males 55%, p = 0.834). Type of disease onset was not related to GI prevalence (earlyonset 50%, late-onset 55.6%, p=0.650). After dividing the patients into groups with a disease duration of <5 years, 5–10 years and >10 years, respectively, the prevalence of GI symptoms was found to be significantly higher in later stages (26.3% vs. 55.0% vs. 78.9%, p = 0.005; OR 2.450, 95% CI 1.084-5.538). Gastrointestinal manifestations had no impact on survival (p=0.193). Conclusions: Gastrointestinal manifestations are very common in hATTR patients with Glu89Gln mutation and increase with disease duration. They are not associated with gender and onset of the disease and have no impact on patient survival. These results highlight the importance of a thorough evaluation of the GI function in patients with ATTR amyloidosis and should stimulate further studies on the phenotypic differences related to genotype and geographic origin.