1-202349078-A-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_002481.4(PPP1R12B):c.227A>G(p.Lys76Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,774 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: PPP1R12B NM_002481.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.18

Genes affected

PPP1R12B (HGNC:7619): (protein phosphatase 1 regulatory subunit 12B) Myosin phosphatase is a protein complex comprised of three subunits: a catalytic subunit (PP1c-delta, protein phosphatase 1, catalytic subunit delta), a large regulatory subunit (MYPT, myosin phosphatase target) and small regulatory subunit (sm-M20). Two isoforms of MYPT have been isolated--MYPT1 and MYPT2, the first of which is widely expressed, and the second of which may be specific to heart, skeletal muscle, and brain. Each of the MYPT isoforms functions to bind PP1c-delta and increase phosphatase activity. This locus encodes both MYTP2 and M20. Alternatively spliced transcript variants encoding different isoforms have been identified. Related pseudogenes have been defined on the Y chromosome. [provided by RefSeq, Oct 2011]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.03545913).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PPP1R12B	NM_002481.4	c.227A>G	p.Lys76Arg	missense_variant	1/24	ENST00000608999.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PPP1R12B	ENST00000608999.6	c.227A>G	p.Lys76Arg	missense_variant	1/24	1	NM_002481.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000120 AC: 3 AN: 249986 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 135512

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000164

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461774 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727184

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000126

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 14, 2023

The c.227A>G (p.K76R) alteration is located in exon 1 (coding exon 1) of the PPP1R12B gene. This alteration results from a A to G substitution at nucleotide position 227, causing the lysine (K) at amino acid position 76 to be replaced by an arginine (R). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.065
BayesDel_addAF	Benign	-0.30	T
BayesDel_noAF	Benign	-0.40
Cadd	Benign	16
Dann	Benign	0.94
Eigen	Benign	-0.77
Eigen_PC	Benign	-0.56
FATHMM_MKL	Benign	0.025	N
LIST_S2	Uncertain	0.88	D;D;D;D
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.035	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-1.4	N;N;N;N
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Uncertain	0.52	T
Sift4G	Benign	1.0	T;T;T;T
Polyphen		0.0	.;B;.;B
Vest4		0.063
MutPred		0.41		Loss of ubiquitination at K76 (P = 0.0341);Loss of ubiquitination at K76 (P = 0.0341);Loss of ubiquitination at K76 (P = 0.0341);Loss of ubiquitination at K76 (P = 0.0341);
MVP		0.48
MPC		0.65
ClinPred		0.063	T
GERP RS		1.6
Varity_R		0.079
gMVP		0.24

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: rs768580152; hg19: chr1-202318206;