Table of Contents
What is SCN1A gene mutation?
SCN1A mutations are the main cause of both Dravet syndrome (DS, MIM 607208) and intractable childhood epilepsy with generalized tonic-clonic seizures, also known as severe idiopathic generalized epilepsy of infancy (Mulley et al., 2005; Fujiwara, 2006).
How do SCN1A mutations cause epilepsy?
Interneurons normally suppress brain cells from generating electrical activity, but in the presence of the SCN1A variant, they are no longer able to adequately suppress electrical activity, leading to a predisposition to seizures.
What chromosome is the SCN1A gene on?
chromosome 2q24
The SCN1A gene is located on the chromosome 2q24, composed of 26 exons spanning 6030 bp and encodes the large α-subunit of the voltage-gated sodium ion channel, type 1 (NaV 1.1)28 (see Figure 1).
Is Dravet syndrome curable?
Although there is no cure for Dravet syndrome, most treatments aim to reduce seizures. First line anti-seizure medications include clobazam (Onfi, Frisium) and valproic acid (Depakote, Depakene).
Is Dravet syndrome genetic?
Most cases of Dravet syndrome occur when the SCN1A gene is not working correctly. It can be inherited in an autosomal dominant pattern, but most people with Dravet syndrome do not have a family history of the condition. Diagnosis is based on a clinical exam, medical history, and the results of genetic testing.
Are you born with Dravet syndrome?
No. In most children (80%), Dravet syndrome is caused by a genetic mutation in the SCN1A gene.
What diseases are caused by gene mutations?
The brains of those with Alzheimer’s present amyloid plaques, which have a level of toxicity believed to cause neuron death. These plaques are formed when the amyloid precursor protein is cleaved by an enzyme called beta-secretase. “The Icelandic mutation makes it harder for this enzyme to cleave the amyloid precursor protein.
What is a natural cause for gene mutation?
Diploid organisms carry two copies (alleles) of each gene,whereas haploidorganisms carry only one copy.
What mutation would not affect the expression of a gene?
Types of Point Mutations. Changes in the number or type of nucleotides are called point mutations. The effects of point mutation can range from harmless to life threatening. Mispairing or reordering of nucleotide bases are considered silent mutations when the change doesn’t affect cell functioning.
Does a SCN1A mutation lead to autism?
Mutations of SCN1A and SCN2A were found in a wide spectrum of epilepsies, intellectual disability, and autism. Nav1.1 protein encoded by SCN1A is densely expressed in parvalbumin-positive inhibitory interneurons and moderately in a subpopulation of excitatory neurons.