Genetic Variant GLRA1:p.Pro278Ser (chr5-151851470-G-A) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM2PM5PP3_Strong

The NM_000171.4(GLRA1):c.832C>T(p.Pro278Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,740 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P278T) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

GLRA1
NM_000171.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.77

Publications

0 publications found

Variant links:

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

GLRA1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_000171.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr5-151851470-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 16066.Status of the report is no_assertion_criteria_provided, 0 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.962

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GLRA1	NM_000171.4 link	c.832C>T	p.Pro278Ser	missense_variant	Exon 7 of 9	ENST00000274576.9	NP_000162.2	P23415-2
GLRA1	NM_001146040.2 link	c.832C>T	p.Pro278Ser	missense_variant	Exon 7 of 9		NP_001139512.1	P23415-1
GLRA1	NM_001292000.2 link	c.583C>T	p.Pro195Ser	missense_variant	Exon 6 of 8		NP_001278929.1	Q14C71
GLRA1	XM_047417105.1 link	c.880C>T	p.Pro294Ser	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 link	c.832C>T	p.Pro278Ser	missense_variant	Exon 7 of 9	1	NM_000171.4	ENSP00000274576.5		P23415-2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461740

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727174

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5756

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111892

Other (OTH)

AF:

0.00

AC:

AN:

60390

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.225

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.33

BayesDel_noAF

Pathogenic

0.24

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

Eigen

Pathogenic

0.90

Eigen_PC

Pathogenic

0.87

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

D;D

M_CAP

Pathogenic

0.41

MetaRNN

Pathogenic

0.96

D;D

MetaSVM

Uncertain

0.79

MutationAssessor

Uncertain

2.3

M;M

PhyloP100

9.8

PrimateAI

Pathogenic

0.87

PROVEAN

Pathogenic

-7.0

D;D

REVEL

Pathogenic

0.86

Sift

Uncertain

0.0020

D;D

Sift4G

Uncertain

0.057

T;D

Polyphen

1.0

D;D

Vest4

0.92

MutPred

0.84

Gain of glycosylation at P278 (P = 0.0564);Gain of glycosylation at P278 (P = 0.0564);

MVP

0.96

MPC

2.1

ClinPred

1.0

GERP RS

5.2

Varity_R

0.85

gMVP

0.97

Mutation Taster

=4/96

disease causing

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over