chr20-8739330-C-T

Variant names:

• chr20-8739330-C-T
• rs1194618095
• NM_015192.4:c.2278C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3_Moderate

The NM_015192.4(PLCB1):​c.2278C>T​(p.Arg760Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000479 in 1,461,240 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R760H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: PLCB1 NM_015192.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.75
• Publications: 4 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.844

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PLCB1	NM_015192.4	c.2278C>T	p.Arg760Cys	missense_variant	Exon 21 of 32	ENST00000338037.11	NP_056007.1
PLCB1	NM_182734.3	c.2278C>T	p.Arg760Cys	missense_variant	Exon 21 of 33		NP_877398.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PLCB1	ENST00000338037.11	c.2278C>T	p.Arg760Cys	missense_variant	Exon 21 of 32	1	NM_015192.4	ENSP00000338185.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251418 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: 0.0000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461240 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 727014

African (AFR) AF: 0.00 AC: 0 AN: 33464

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86244

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: 0.00000540 AC: 6 AN: 1111412

Other (OTH) AF: 0.00 AC: 0 AN: 60382

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 12 Uncertain:1

Oct 30, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine with cysteine at codon 760 of the PLCB1 protein (p.Arg760Cys). The arginine residue is highly conserved and there is a large physicochemical difference between arginine and cysteine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a PLCB1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.65
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	0.090
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.76	.;.;.;D;.;T;.;T;D
Eigen	Pathogenic	0.76
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	1.0	D;D;.;D;D;D;D;D;D
M_CAP	Benign	0.019	T
MetaRNN	Pathogenic	0.84	D;D;D;D;D;D;D;D;D
MetaSVM	Benign	-0.97	T
MutationAssessor	Uncertain	2.8	.;.;M;M;M;.;.;.;.
PhyloP100		4.8
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-7.3	.;.;D;D;D;.;.;.;D
REVEL	Uncertain	0.34
Sift	Pathogenic	0.0	.;.;D;D;D;.;.;.;D
Sift4G	Pathogenic	0.0	.;D;D;D;D;D;D;D;D
Polyphen		1.0, 1.0	.;.;D;D;D;.;.;.;.
Vest4		0.77, 0.80, 0.77
MutPred		0.64		.;.;Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);.;.;.;.;
MVP		0.85
MPC		2.6
ClinPred		1.0	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.82
gMVP		0.93
Mutation Taster		=41/59	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.18		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: rs1194618095; hg19: chr20-8719977; COSMIC: COSV62062279;