Search results for " Potassium"

Association of a functional deficit of the BKCa channel, a synaptic regulator of neuronal excitability, with autism and mental retardation

2006

International audience; Objective: Autism is a complex, largely genetic psychiatric disorder. In the majority of cases, the cause of autism is not known, but there is strong evidence for a genetic etiology. To identify candidate genes, the physical mapping of balanced chromosomal aberrations is a powerful strategy, since several genes have been characterized in numerous disorders. In this study, the authors analyzed a balanced reciprocal translocation arising de novo in a subject with autism and mental retardation. Method: The authors performed the physical mapping of the balanced 9q23/ 10q22 translocation by fluorescent in situ hybridization experiments using bacterial artificial chromosom…

Inhibition by Anandamide and Synthetic Cannabimimetics of the Release of [3H]d-Aspartate and [3H]GABA from Synaptosomes Isolated from the Rat Hippoca…

2004

Cannabinoids (CB) can act as retrograde synaptic mediators of depolarization-induced suppression of inhibition or excitation in hippocampus. This mechanism may underlie the impairment of some cognitive processes produced by these compounds, including short-term memory formation in the hippocampus. In this study, we investigated several compounds known to interact with CB receptors, evaluating their effects on K +-evoked release of [ 3H]d-aspartate ([ 3H]d-ASP) and [ 3H]GABA from superfused synaptosomes isolated from the rat hippocampus. [ 3H]d-ASP and [ 3H]GABA release were inhibited to different degrees by the synthetic cannabinoids WIN 55,212-2; CP 55,940, and arachidonyl-2′- chloroethyla…

Postnatal increases in axonal conduction velocity of an identified Drosophila interneuron require fast sodium, L-type calcium and shaker potassium ch…

2019

Abstract During early postnatal life, speed up of signal propagation through many central and peripheral neurons has been associated with an increase in axon diameter or/and myelination. Especially in unmyelinated axons postnatal adjustments of axonal membrane conductances is potentially a third mechanism but solid evidence is lacking. Here, we show that axonal action potential (AP) conduction velocity in the Drosophila giant fiber (GF) interneuron, which is required for fast long-distance signal conduction through the escape circuit, is increased by 80% during the first day of adult life. Genetic manipulations indicate that this postnatal increase in AP conduction velocity in the unmyelina…

Additional evidence to support the role of the 20q13.33 region in susceptibility to autism

2012

Massive digoxin intoxication in childhood.

1978

In a 10 year old boy 8 hours after taking about 16 mg beta-acetyl-digoxin a maximum serum digoxin level of 31.8 ng/ml was measured radioimmunologically. This is the highest digitalis level in childhood described to date. The serum potassium level rose to 7.4 mmol/l. Complete atrio-ventricular block, and salves of ventricular premature beats were the most serious rhythm disturbances. The absence of life threatening rhythm disturbances is attributed to the early use of diphenylhydantoin in small frequent doses.

Benign familial infantile epilepsy associated with KCNQ3 mutation: a rare occurrence or an underestimated event?

2020

Abstract Benign familial infantile epilepsy (BFIE) is the most genetically heterogeneous phenotype among early-onset familial infantile epilepsies. It has an autosomal dominant inheritance pattern with incomplete penetrance. Although PRRT2 is the most mutated gene detected in families with BFIE, other mutations in KCNQ2, SCN2A, and GABRA6 genes have also been described. To date, KCNQ3 mutations have been detected in only four patients with BFIE. Here, we describe the clinical pattern and course of an additional individual with BFIE associated with a novel missense heterozygous KCNQ3 c.1850G>C variant inherited by his unaffected father. The incidence of KCNQ3 mutations among BFIE patients…

A novel mutation in KCNQ3-related benign familial neonatal epilepsy: electroclinical features and neurodevelopmental outcome.

2019

Benign familial neonatal epilepsy (BFNE) is caused, in about 5% of families, by mutations in the KCNQ3 gene encoding voltage-gated potassium channel subunits. Usually, newborns with BFNE show a normal neurological outcome, but recently, refractory seizures and/or developmental disability have been reported suggesting phenotype variability associated with KCNQ3-related BFNE. Here, we describe a proband from a BFNE family carrying a novel variant in the KCNQ3 gene. Regarding the paucity of data in the literature, we describe the presented case with a view to further establishing: (1) a genotype/phenotype correlation in order to define a BFNE phenotype associated with favourable outcome; (2) a…

A novel KCNQ3 mutation in familial epilepsy with focal seizures and intellectual disability

2015

Mutations in the KCNQ2 gene encoding for voltage-gated potassium channel subunits have been found in patients affected with early onset epilepsies with wide phenotypic heterogeneity, ranging from benign familial neonatal seizures (BFNS) to epileptic encephalopathy with cognitive impairment, drug resistance, and characteristic electroencephalography (EEG) and neuroradiologic features. By contrast, only few KCNQ3 mutations have been rarely described, mostly in patients with typical BFNS. We report clinical, genetic, and functional data from a family in which early onset epilepsy and neurocognitive deficits segregated with a novel mutation in KCNQ3 (c.989G>T; p.R330L). Electrophysiological stu…

Long-Term Potassium Monitoring and Dynamics in Heart Failure and Risk of Mortality

2018

Background: The prognostic value of long-term potassium monitoring and dynamics in heart failure has not been characterized completely. We sought to determine the association between serum potassium values collected at follow-up with all-cause mortality in a prospective and consecutive cohort of patients discharged from a previous acute heart failure admission. Methods: Serum potassium was measured at every physician-patient encounter, including hospital admissions and ambulatory settings. The multivariable-adjusted association of serum potassium with mortality was assessed by using comprehensive state-of-the-art regression methods that can accommodate time-dependent exposure modeling. Res…

A de novo heterozygous mutation in KCNC2 gene implicated in severe developmental and epileptic encephalopathy

2020

Abstract An increasing number of developmental and epileptic encephalopathies have been correlated with variants of ion channel genes, and in particular of potassium channels genes, such as KCNA1, KCNA2, KCNB1, KCNQ2, KCTD7 and KCNT1. Here we report a child with an early severe developmental and epileptic encephalopathy, spastic tetraplegia, opisthotonos attacks. The whole exome sequencing showed the de novo heterozygous variant c.1411G > C (p.Val471Leu) in the KCNC2 gene. Although this is, to our knowledge, the first case of encephalopathy associated with a KCNC2 gene variant, and further confirmatory studies are needed, previous preclinical and clinical evidence seems to suggest that KCNC…