chr2-28776944-C-G

Position:

• chr2-28776944-C-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PP2 PS4 PS2 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The c.146C>G (Pro49Arg) variant in PPP1CB is a missense variant predicted to cause substitution of proline by arginine at amino acid 49. This variant is absent from gnomAD v4 (PM2_Supporting). PPP1CB, in which the variant was identified, is defined by the ClinGen RASopathy VCEP as a gene that has a low rate of benign missense variation and where pathogenic missense variants are a common mechanism of disease (PP2). The missense Z-score is 4.33 which is above the threshold set by the Rasopathy VCEP. The computational predictor REVEL gives a score of 0.438, which is neither above nor below the thresholds predicting a damaging or benign impact on PPP1CB function. This variant has been reported in 13 probands with features of RASopathy (PS4; PMIDs: 27264673, 27681385, 27868344, 28211982, 30368668, 32476286). This variant has been identified as a de novo occurrence with confirmed parental relationships in 9 individuals and as a de novo occurrence with unconfirmed parental relationships in 2 individuals with features of RASopathy (PS2_VeryStrong; PMIDs: 27264673, 27681385, 27868344). In summary, this variant meets the criteria to be classified as pathogenic for autosomal dominant RASopathy based on the ACMG/AMP criteria applied, as specified by the ClinGen RASopathy VCEP: PS2_VS, PS4, PM2_P, PP2. (RASopathy VCEP specifications version 1.1; 9/17/2024) LINK:https://erepo.genome.network/evrepo/ui/classification/CA10586682/MONDO:0021060/128

• Frequency: Genomes: not found (cov: 32)
• Consequence: PPP1CB NM_002709.3 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:27
• Conservation: PhyloP100: 7.91

Genes affected

PPP1CB (HGNC:9282): (protein phosphatase 1 catalytic subunit beta) The protein encoded by this gene is one of the three catalytic subunits of protein phosphatase 1 (PP1). PP1 is a serine/threonine specific protein phosphatase known to be involved in the regulation of a variety of cellular processes, such as cell division, glycogen metabolism, muscle contractility, protein synthesis, and HIV-1 viral transcription. Mouse studies suggest that PP1 functions as a suppressor of learning and memory. Two alternatively spliced transcript variants encoding distinct isoforms have been observed. [provided by RefSeq, Jul 2008]

PPP1CB (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PS2: For more information check the summary or visit ClinGen Evidence Repository.
• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP2: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PPP1CB	NM_002709.3	c.146C>G	p.Pro49Arg	missense_variant	2/8	ENST00000395366.3	NP_002700.1
PPP1CB	NM_206876.2	c.146C>G	p.Pro49Arg	missense_variant	3/9		NP_996759.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PPP1CB	ENST00000395366.3	c.146C>G	p.Pro49Arg	missense_variant	2/8	1	NM_002709.3	ENSP00000378769.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:27

Revision: reviewed by expert panel

Submissions by phenotype

Noonan syndrome-like disorder with loose anagen hair 2 Pathogenic:11

Likely pathogenic, no assertion criteria provided	research	Lupski Lab, Baylor-Hopkins CMG, Baylor College of Medicine	Jun 29, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Jul 17, 2023	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0101 - Gain of function is a known mechanism of disease in this gene and is associated with Noonan syndrome-like disorder with loose anagen hair 2 (MIM#617506) (PMID: 30348783). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from proline to arginine. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0603 - Missense variant in a region that is highly intolerant to missense variation (high constraint region in DECIPHER). (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This is a recurrent variant reported in multiple individuals with Noonan syndrome-like disorder with loose anagen hair 2 (MIM#617506) (ClinVar, DECIPHER, PMID: 33491856). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratory of Medical Genetics, National & Kapodistrian University of Athens	Oct 05, 2021	PM2, PP2, PP3, PP5 -
Pathogenic, no assertion criteria provided	literature only	OMIM	May 31, 2017	- -
Pathogenic, no assertion criteria provided	clinical testing	Coyote Medical Laboratory (Beijing), Coyote	May 28, 2018	- -
Pathogenic, no assertion criteria provided	clinical testing	Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille	Jan 01, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Department of Endocrinology and Genetics, Fuzhou Children’s Hospital of Fujian Medical University	Sep 08, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	Oct 02, 2021	Same nucleotide change resulting in same amino acid change has been previously reported as de novoo and observed in at least four similarly affected unrelated individuals (PMID: 27264673, 28211982 and 27681385, PS2 and PS4). It is not observed in the gnomAD v2.1.1 dataset (PM2). The variant was observed as assumed (i.e. paternity and maternity not confirmed) de novoo (3billion dataset, PM6). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -
Pathogenic, criteria provided, single submitter	clinical testing	Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego	-	This variant has been previously reported as a de novo heterozygous variant in multiple unrelated individuals with Noonan-like syndrome with loose anagen hair (PMID: 27264673, 27681385, 27868344, 28211982, 31474318). It is absent from the gnomAD population database and thus is presumed to be rare. The c.146C>G (p.Pro49Arg) variant is predicted by multiple in silico tools to have a deleterious effect on protein function. Based on the available evidence, the c.146C>G (p.Pro49Arg) variant is classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Equipe Genetique des Anomalies du Developpement, Université de Bourgogne	May 04, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Molecular Genetics Laboratory, BC Children's and BC Women's Hospitals	Jul 09, 2024	- -

not provided Pathogenic:11

Pathogenic, criteria provided, single submitter	clinical testing	Blueprint Genetics	Nov 07, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 07, 2023	This missense change has been observed in individual(s) with Noonan syndrome-like disorder with loose anagen hair (NSLDH) (PMID: 27264673, 27681385, 27868344, 28211982). In at least one individual the variant was observed to be de novo. For these reasons, this variant has been classified as Pathogenic. 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 disruptive. ClinVar contains an entry for this variant (Variation ID: 254648). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces proline, which is neutral and non-polar, with arginine, which is basic and polar, at codon 49 of the PPP1CB protein (p.Pro49Arg). -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Oct 05, 2021	In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Not observed in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 27264673, 27868344, 27338287, 28211982, 27681385, 28135719, 30368668, 31474318, 31370276, 32476286) -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jun 15, 2018	- -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Oct 23, 2020	- -
Pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics	Aug 30, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Apr 01, 2023	PPP1CB: PS2, PM2, PS4:Moderate, PP2, PP4 -
Pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -

Neurodevelopmental delay Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille

-

- -

Dandy-Walker syndrome Pathogenic:1

Likely pathogenic, no assertion criteria provided

research

University of Washington Center for Mendelian Genomics, University of Washington

-

- -

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 06, 2016

- -

Noonan syndrome Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Service de Génétique Moléculaire, Hôpital Robert Debré

-

- -

RASopathy Pathogenic:1

Pathogenic, reviewed by expert panel

curation

ClinGen RASopathy Variant Curation Expert Panel

Sep 17, 2024

The c.146C>G (Pro49Arg) variant in PPP1CB is a missense variant predicted to cause substitution of proline by arginine at amino acid 49. This variant is absent from gnomAD v4 (PM2_Supporting). PPP1CB, in which the variant was identified, is defined by the ClinGen RASopathy VCEP as a gene that has a low rate of benign missense variation and where pathogenic missense variants are a common mechanism of disease (PP2). The missense Z-score is 4.33 which is above the threshold set by the Rasopathy VCEP. The computational predictor REVEL gives a score of 0.438, which is neither above nor below the thresholds predicting a damaging or benign impact on PPP1CB function. This variant has been reported in 13 probands with features of RASopathy (PS4; PMIDs: 27264673, 27681385, 27868344, 28211982, 30368668, 32476286). This variant has been identified as a de novo occurrence with confirmed parental relationships in 9 individuals and as a de novo occurrence with unconfirmed parental relationships in 2 individuals with features of RASopathy (PS2_VeryStrong; PMIDs: 27264673, 27681385, 27868344). In summary, this variant meets the criteria to be classified as pathogenic for autosomal dominant RASopathy based on the ACMG/AMP criteria applied, as specified by the ClinGen RASopathy VCEP: PS2_VS, PS4, PM2_P, PP2. (RASopathy VCEP specifications version 1.1; 9/17/2024) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Benign	0.19	.;.;T;D;D;D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D;D;.;.
M_CAP	Benign	0.050	D
MetaRNN	Pathogenic	0.84	D;D;D;D;D;D
MetaSVM	Uncertain	0.33	D
MutationAssessor	Pathogenic	4.8	.;.;.;H;H;H
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-8.0	D;D;D;D;D;D
REVEL	Uncertain	0.44
Sift	Pathogenic	0.0	D;D;D;D;D;D
Sift4G	Uncertain	0.0060	D;D;D;D;D;D
Polyphen		1.0	.;.;.;D;D;D
Vest4		0.96, 0.97
MutPred		0.53		.;Loss of catalytic residue at L46 (P = 0.1248);Loss of catalytic residue at L46 (P = 0.1248);Loss of catalytic residue at L46 (P = 0.1248);Loss of catalytic residue at L46 (P = 0.1248);Loss of catalytic residue at L46 (P = 0.1248);
MVP		0.65
MPC		2.8
ClinPred		1.0	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.88
gMVP		0.98

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

LitVar

Other links and lift over

dbSNP: rs886037952; hg19: chr2-28999810;