rs878853281

Variant names:

• chr9-109141360-C-T
• rs878853281
• NM_014334.4:c.692G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_014334.4(FRRS1L):​c.692G>A​(p.Trp231*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,862 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: FRRS1L NM_014334.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:3
• Conservation: PhyloP100: 7.91
• Publications: 1 publications found

Genes affected

FRRS1L (HGNC:1362): (ferric chelate reductase 1 like) This gene encodes a component of the outer-core of an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor protein in the brain. The encoded protein is thought to interact with inner-core components of the receptor, and play a role in the modulation of glutamate signaling. Mutations in this gene are associated with early infantile epileptic encephalopathy 37. [provided by RefSeq, Jul 2016]

FRRS1L Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 37

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• autosomal recessive non-syndromic intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.215 CDS is truncated, and there are 3 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-109141360-C-T is Pathogenic according to our data. Variant chr9-109141360-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 218152.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_014334.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FRRS1L	NM_014334.4	MANE Select	c.692G>A	p.Trp231*	stop_gained	Exon 4 of 5	NP_055149.3

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FRRS1L	ENST00000561981.5	TSL:1 MANE Select	c.692G>A	p.Trp231*	stop_gained	Exon 4 of 5	ENSP00000477141.2
	FRRS1L	ENST00000642157.1		n.2927G>A		non_coding_transcript_exon	Exon 3 of 3
	FRRS1L	ENST00000644736.1		n.*664G>A		non_coding_transcript_exon	Exon 5 of 6	ENSP00000494579.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251408 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461862 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727228

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111986

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 37 Pathogenic:2

Jan 18, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ClinVar contains an entry for this variant (Variation ID: 218152). This premature translational stop signal has been observed in individual(s) with early infantile epileptic encephalopathy (PMID: 27236917; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This sequence change creates a premature translational stop signal (p.Trp282*) in the FRRS1L gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 63 amino acid(s) of the FRRS1L protein. Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the FRRS1L protein in which other variant(s) (p.Arg292*, p.Gln321*) have been determined to be pathogenic (PMID: 27236917; Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. Experimental studies have shown that this premature translational stop signal affects FRRS1L function (PMID: 27236917).

Oct 23, 2020

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

Chorea;C0036572:Seizure;C1838578:Progressive encephalopathy Pathogenic:1

Nov 11, 2015

Kruer lab, Phoenix Children's Hospital

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

Leads to loss of protein by immunoblot; leads to impaired co-localization with GluR1 component of AMPA receptor by TIRF; loss of FRRS1L leads to attenuated AMPA currents by electrophysiology

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	45
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.9
Vest4		0.43
GERP RS		5.6
Mutation Taster		=5/195	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.41		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.41		Position offset: -17

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs878853281; hg19: chr9-111903640;