20-8132680-C-T

Variant names:

• chr20-8132680-C-T
• rs1568564198
• NM_015192.4:c.29C>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_015192.4(PLCB1):​c.29C>T​(p.Ala10Val) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign 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. A10S) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PLCB1 NM_015192.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.72
• Publications: 0 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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.32478583).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PLCB1	NM_015192.4	c.29C>T	p.Ala10Val	missense_variant	Exon 1 of 32	ENST00000338037.11	NP_056007.1
PLCB1	NM_182734.3	c.29C>T	p.Ala10Val	missense_variant	Exon 1 of 33		NP_877398.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PLCB1	ENST00000338037.11	c.29C>T	p.Ala10Val	missense_variant	Exon 1 of 32	1	NM_015192.4	ENSP00000338185.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 12 Uncertain:1

Jul 31, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine with valine at codon 10 of the PLCB1 protein (p.Ala10Val). The alanine residue is weakly conserved and there is a small physicochemical difference between alanine and valine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with PLCB1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.44
BayesDel_addAF	Benign	-0.074	T
BayesDel_noAF	Benign	-0.34
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.26	.;T;.;.;.
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.96	.;D;D;D;D
M_CAP	Uncertain	0.27	D
MetaRNN	Benign	0.32	T;T;T;T;T
MetaSVM	Benign	-0.73	T
MutationAssessor	Benign	1.9	L;L;.;.;L
PhyloP100		6.7
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	-1.0	N;N;.;.;N
REVEL	Benign	0.16
Sift	Benign	0.31	T;T;.;.;T
Sift4G	Benign	0.27	T;T;D;D;T
Polyphen		1.0	D;D;.;.;D
Vest4		0.48
MutPred		0.33		Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);
MVP		0.33
MPC		0.10
ClinPred		0.98	D
GERP RS		4.8
PromoterAI		0.055	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.26
gMVP		0.43
Mutation Taster		=33/67	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: rs1568564198; hg19: chr20-8113327;