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EpiFirst-IS®

Infantile spasms (IS) are characterized by epileptic spasms, sometimes associated with hypsarrhythmia on EEG and developmental regression. Genetic testing can be helpful in distinguishing the underlying molecular mechanism, which can be critical to guiding appropriate treatment, prognosis, and genetic counseling.
EpiFirst-IS by Ambry Genetics| Genetic test for Infantile Spasms

Infantile spasms (IS) are characterized by epileptic spasms, sometimes associated with hypsarrhythmia on EEG and developmental regression. Genetic testing can be helpful in distinguishing the underlying molecular mechanism, which can be critical to guiding appropriate treatment, prognosis, and genetic counseling.

EpiFirst-IS includes 17 genes (listed above). All of these genes are included in our comprehensive epilepsy panel, EpilepsyNext, as well. Genomic deoxyribonucleic acid (gDNA) is isolated from the patient’s specimen using a standardized methodology and quantified. Sequence enrichment of the targeted coding exons and adjacent intronic nucleotides is carried out by a bait-capture methodology using long biotinylated oligonucleotide probes, followed by polymerase chain reaction (PCR) and next generation sequencing (NGS).

Additional Sanger sequencing is performed for any regions missing or with insufficient read depth coverage for reliable heterozygous variant detection. Potentially homozygous variants, variants in regions complicated by pseudogene interference, and variant calls not satisfying depth of coverage and variant allele frequency quality thresholds are verified by Sanger sequencing. This assay targets all coding domains, and well into the flanking 5’ and 3’ ends of all the introns and untranslated regions. Gross deletion/duplication analysis for available genes is performed using a custom pipeline based on read-depth from NGS data and/or targeted chromosomal microarray with confirmatory MLPA when applicable.

Genes analyzed
Code
Test Name
Turnaround
Genes
EpiFirst-IS
14-21 days
17 Genes
EpiFirst-IS
17 Genes
ARX
CDKL5
DNM1
EEF1A2
FOXG1
GRIN1
GRIN2A
KCNQ2
KCNT1
SCN2A
SCN8A
SIK1
SLC25A22
SPTAN1
STXBP1
TSC1
TSC2
Test Requisition Form
Neurology
Consent
Reference Guide
Child Neurology Genetic Testing
Clinician Management Resources + Understanding Your Results
Epilepsy Carrier
Negative Epilepsy
Positive Epilepsy
VUS Epilepsy

Test Description

Ambry Genetics neurology panels are completed via whole exome capture with targeted analysis of clinically relevant gene lists.FMR1 repeat expansion testing is not included in this test, but can be ordered concurrently. Genomic deoxyribonucleic acid (gDNA) is isolated from the patient’s specimen using a standardized methodology and quantified. Each DNA sample is sheared, adaptor ligated, PCR-amplified and incubated with the exome baits. Captured DNA is eluted, and PCR amplified. Final quantified libraries are seeded onto an Illumina flow cell and sequenced using paired-end, 150 cycle chemistry on the Illumina HiSeq or NextSeq.

Coding exons plus at least 6 bases into the 5’ and 3’ ends of all the introns are analyzed and reported. Gross deletion/duplication analysis is assessed for all genes within the targeted exome using a custom pipeline based on coverage (>4 exons in size) and/or breakpoint analysis from NGS data and confirmed by targeted chromosomal microarray, SNP array or MLPA when applicable. CNVs detected by NGS pipeline for which no orthogonal method of confirmation is available will not be included.Variants of uncertain significance (VUS), if present, are not routinely reported, unless the ordering provider opts-in to VUS reporting at the time of ordering.

When familial samples are received, co-segregation analysis of potentially informative alterations will be performed, except for gross deletions/duplications which are confirmed in the proband only. Co-segregation results may be confounded by many factors which cannot be completely ruled out including reduced penetrance, age-of-onset, and/or variable expressivity. In most cases, phase cannot be determined

1. Ambry Genetics, internal data on file

2. LaDuca H, Farwell KD, Vuong H, et al., 2017. PLoS ONE 12(2):e0170843