20-44115739-T-C

Variant names:

• chr20-44115739-T-C
• rs747762930
• NM_020433.5:c.1936A>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_020433.5(JPH2):​c.1936A>G​(p.Thr646Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict 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. T646S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: JPH2 NM_020433.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.415
• Publications: 0 publications found

Genes affected

JPH2 (HGNC:14202): (junctophilin 2) Junctional complexes between the plasma membrane and endoplasmic/sarcoplasmic reticulum are a common feature of all excitable cell types and mediate cross talk between cell surface and intracellular ion channels. The protein encoded by this gene is a component of junctional complexes and is composed of a C-terminal hydrophobic segment spanning the endoplasmic/sarcoplasmic reticulum membrane and a remaining cytoplasmic domain that shows specific affinity for the plasma membrane. This gene is a member of the junctophilin gene family. Alternative splicing has been observed at this locus and two variants encoding distinct isoforms are described. [provided by RefSeq, Jul 2008]

JPH2 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy 17

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae)
• cardiomyopathy, dilated, 2E

  Inheritance: Unknown, AR Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: MODERATE Submitted by: ClinGen
• dilated cardiomyopathy

  Inheritance: SD Classification: MODERATE Submitted by: ClinGen

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.035376787).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
JPH2	NM_020433.5	c.1936A>G	p.Thr646Ala	missense_variant	Exon 4 of 6	ENST00000372980.4	NP_065166.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
JPH2	ENST00000372980.4	c.1936A>G	p.Thr646Ala	missense_variant	Exon 4 of 6	5	NM_020433.5	ENSP00000362071.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1461136 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 726960

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26120

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52960

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5620

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111952

Other (OTH) AF: 0.00 AC: 0 AN: 60358

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

May 16, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 646 of the JPH2 protein (p.Thr646Ala). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with JPH2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The alanine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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	Benign	0.075
BayesDel_addAF	Benign	-0.32	T
BayesDel_noAF	Benign	-0.70
CADD	Benign	14
DANN	Benign	0.60
DEOGEN2	Benign	0.055	T
Eigen	Benign	-0.89
Eigen_PC	Benign	-0.75
FATHMM_MKL	Benign	0.044	N
LIST_S2	Benign	0.33	T
M_CAP	Uncertain	0.099	D
MetaRNN	Benign	0.035	T
MetaSVM	Benign	-0.90	T
MutationAssessor	Benign	-0.81	N
PhyloP100		-0.41
PrimateAI	Uncertain	0.74	T
PROVEAN	Benign	-0.48	N
REVEL	Benign	0.089
Sift	Benign	1.0	T
Sift4G	Benign	0.81	T
Polyphen		0.0	B
Vest4		0.057
MutPred		0.14		Loss of phosphorylation at T646 (P = 0.0057);
MVP		0.59
ClinPred		0.029	T
GERP RS		1.1
Varity_R		0.077
gMVP		0.16
Mutation Taster		=88/12	polymorphism

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: rs747762930; hg19: chr20-42744379;