5-151851501-C-A

Variant names:

• chr5-151851501-C-A
• rs281864917
• NM_000171.4:c.801G>T

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PS1 PM1 PM2 PP3_Strong PP5_Moderate

The NM_000171.4(GLRA1):​c.801G>T​(p.Trp267Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W267R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GLRA1 NM_000171.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.73
• Publications: 0 publications found

Genes affected

GLRA1 (HGNC:4326): (glycine receptor alpha 1) The protein encoded by this gene is a subunit of a pentameric inhibitory glycine receptor, which mediates postsynaptic inhibition in the central nervous system. Defects in this gene are a cause of startle disease (STHE), also known as hereditary hyperekplexia or congenital stiff-person syndrome. Multiple transcript variants encoding different isoforms have been found. [provided by RefSeq, Dec 2015]

GLRA1 Gene-Disease associations (from GenCC):

• hyperekplexia 1

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• hereditary hyperekplexia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PS1: Transcript NM_000171.4 (GLRA1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_000171.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 5-151851501-C-A is Pathogenic according to our data. Variant chr5-151851501-C-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2708040.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GLRA1	NM_000171.4	c.801G>T	p.Trp267Cys	missense_variant	Exon 7 of 9	ENST00000274576.9	NP_000162.2
GLRA1	NM_001146040.2	c.801G>T	p.Trp267Cys	missense_variant	Exon 7 of 9		NP_001139512.1
GLRA1	NM_001292000.2	c.552G>T	p.Trp184Cys	missense_variant	Exon 6 of 8		NP_001278929.1
GLRA1	XM_047417105.1	c.849G>T	p.Trp283Cys	missense_variant	Exon 7 of 9		XP_047273061.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GLRA1	ENST00000274576.9	c.801G>T	p.Trp267Cys	missense_variant	Exon 7 of 9	1	NM_000171.4	ENSP00000274576.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary hyperekplexia Pathogenic:1

Feb 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tryptophan, which is neutral and slightly polar, with cysteine, which is neutral and slightly polar, at codon 267 of the GLRA1 protein (p.Trp267Cys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of autosomal recessive hyperekplexia (PMID: 15771552; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GLRA1 protein function with a positive predictive value of 95%. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.56	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.90	D
MutationAssessor	Pathogenic	3.5	H;H
PhyloP100		7.7
PrimateAI	Pathogenic	0.95	D
PROVEAN	Pathogenic	-12	D;D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.98
MutPred		0.93		Gain of catalytic residue at S269 (P = 0.069);Gain of catalytic residue at S269 (P = 0.069);
MVP		0.95
MPC		2.5
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.93
gMVP		1.0
Mutation Taster		=1/99	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs281864917; hg19: chr5-151231062;