Genetic Variant PLCB1:p.Gln5* (chr20-8132664-C-T) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_StrongPM2

The NM_015192.4(PLCB1):c.13C>T(p.Gln5*) variant causes a stop gained change. The variant allele was found at a frequency of 0.000000685 in 1,459,312 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

PLCB1
NM_015192.4 stop_gained

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 5.05

Publications

0 publications found

Variant links:

Genes affected

PLCB1 (HGNC:15917): (phospholipase C beta 1) The protein encoded by this gene catalyzes the formation of inositol 1,4,5-trisphosphate and diacylglycerol from phosphatidylinositol 4,5-bisphosphate. This reaction uses calcium as a cofactor and plays an important role in the intracellular transduction of many extracellular signals. This gene is activated by two G-protein alpha subunits, alpha-q and alpha-11. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

PLCB1 Gene-Disease associations (from GenCC):

genetic developmental and epileptic encephalopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
developmental and epileptic encephalopathy, 12
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
infantile spasms
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
malignant migrating partial seizures of infancy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

PLCB1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 14 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PLCB1	NM_015192.4 link	c.13C>T	p.Gln5*	stop_gained	Exon 1 of 32	ENST00000338037.11	NP_056007.1	Q9NQ66-1
PLCB1	NM_182734.3 link	c.13C>T	p.Gln5*	stop_gained	Exon 1 of 33		NP_877398.1	Q9NQ66-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PLCB1	ENST00000338037.11 link	c.13C>T	p.Gln5*	stop_gained	Exon 1 of 32	1	NM_015192.4	ENSP00000338185.6		Q9NQ66-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1459312

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726044

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:

33292

American (AMR)

AF:

0.00

AC:

AN:

44560

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26050

East Asian (EAS)

AF:

0.00

AC:

AN:

39600

South Asian (SAS)

AF:

0.00

AC:

AN:

86044

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53074

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5738

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1110732

Other (OTH)

AF:

0.00

AC:

AN:

60222

⚠️ 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: 0.375

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

BayesDel_addAF

Pathogenic

0.57

BayesDel_noAF

Pathogenic

0.58

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

0.85

Eigen_PC

Pathogenic

0.71

FATHMM_MKL

Uncertain

0.89

PhyloP100

5.1

Vest4

0.70

GERP RS

4.8

PromoterAI

0.0079

Neutral

(source)

Mutation Taster

=16/184

disease causing (fs/PTC)

(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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20-8132664-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over