2-47161814-CAT-AAG

Variant names:

• chr2-47161814-CAT-AAG
• NM_001743.6:c.328_330delATGinsCTT
• CALM2 p.Met110Leu

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PS1_Moderate PM1 PP2 PP3

The NM_001743.6(CALM2):​c.328_330delATGinsCTT​(p.Met110Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar.

• Frequency: Genomes: not found (cov: 30)
• Consequence: CALM2 NM_001743.6 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.29
• Publications: 0 publications found

Genes affected

CALM2 (HGNC:1445): (calmodulin 2) This gene is a member of the calmodulin gene family. There are three distinct calmodulin genes dispersed throughout the genome that encode the identical protein, but differ at the nucleotide level. Calmodulin is a calcium binding protein that plays a role in signaling pathways, cell cycle progression and proliferation. Several infants with severe forms of long-QT syndrome (LQTS) who displayed life-threatening ventricular arrhythmias together with delayed neurodevelopment and epilepsy were found to have mutations in either this gene or another member of the calmodulin gene family (PMID:23388215). Mutations in this gene have also been identified in patients with less severe forms of LQTS (PMID:24917665), while mutations in another calmodulin gene family member have been associated with catecholaminergic polymorphic ventricular tachycardia (CPVT)(PMID:23040497), a rare disorder thought to be the cause of a significant fraction of sudden cardiac deaths in young individuals. Pseudogenes of this gene are found on chromosomes 10, 13, and 17. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Mar 2015]

CALM2 Gene-Disease associations (from GenCC):

• long QT syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• long QT syndrome 15

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• catecholaminergic polymorphic ventricular tachycardia

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, ClinGen, G2P

ENSG00000273269 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PS1: Transcript NM_001743.6 (CALM2) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_001743.6
• PP2: Missense variant in the CALM2 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 18 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Gene score misZ: 2.7928 (below the threshold of 3.09). Trascript score misZ: 3.5506 (above the threshold of 3.09). GenCC associations: The gene is linked to catecholaminergic polymorphic ventricular tachycardia, long QT syndrome, long QT syndrome 15.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001743.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CALM2	NM_001743.6	MANE Select	c.328_330delATGinsCTT	p.Met110Leu	missense	N/A	NP_001734.1	P0DP24
	CALM2	NM_001305624.1		c.472_474delATGinsCTT	p.Met158Leu	missense	N/A	NP_001292553.1	P0DP24
	CALM2	NM_001305625.2		c.220_222delATGinsCTT	p.Met74Leu	missense	N/A	NP_001292554.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CALM2	ENST00000272298.12	TSL:1 MANE Select	c.328_330delATGinsCTT	p.Met110Leu	missense	N/A	ENSP00000272298.7	P0DP24
	CALM2	ENST00000460218.5	TSL:1	n.3768_3770delATGinsCTT		non_coding_transcript_exon	Exon 4 of 5
	ENSG00000273269	ENST00000422269.1	TSL:2	n.101-8800_101-8798delATGinsCTT		intron	N/A	ENSP00000476793.1	V9GYI7

Frequencies

GnomAD3 genomes Cov.: 30

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 30

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr2-47388953;