rs773827877

Positions:

• chr15-42399631-G-A
• chr15-42399631-G-C

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PS1 PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000070.3(CAPN3):​c.1333G>A​(p.Gly445Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000344 in 1,453,300 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another nucleotide change resulting in same amino acid change has been previously reported as Pathogenicin Lovd.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: CAPN3 NM_000070.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11
• Conservation: PhyloP100: 10.0

Genes affected

CAPN3 (HGNC:1480): (calpain 3) Calpain, a heterodimer consisting of a large and a small subunit, is a major intracellular protease, although its function has not been well established. This gene encodes a muscle-specific member of the calpain large subunit family that specifically binds to titin. Mutations in this gene are associated with limb-girdle muscular dystrophies type 2A. Alternate promoters and alternative splicing result in multiple transcript variants encoding different isoforms and some variants are ubiquitously expressed. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 20 ACMG points.

• PS1: Transcript NM_000070.3 (CAPN3) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in Lovd
• PM1: In a region_of_interest Domain III (size 168) in uniprot entity CAN3_HUMAN there are 132 pathogenic changes around while only 0 benign (100%) in NM_000070.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 15-42399631-G-A is Pathogenic according to our data. Variant chr15-42399631-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 284515.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr15-42399631-G-A is described in Lovd as [Pathogenic]. Variant chr15-42399631-G-A is described in Lovd as [Pathogenic]. Variant chr15-42399631-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CAPN3	NM_000070.3	c.1333G>A	p.Gly445Arg	missense_variant	10/24	ENST00000397163.8	NP_000061.1
CAPN3	NM_024344.2	c.1333G>A	p.Gly445Arg	missense_variant	10/23		NP_077320.1
CAPN3	NM_173087.2	c.1189G>A	p.Gly397Arg	missense_variant	9/21		NP_775110.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CAPN3	ENST00000397163.8	c.1333G>A	p.Gly445Arg	missense_variant	10/24	1	NM_000070.3	ENSP00000380349	P2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.0000125 AC: 3 AN: 240268 Hom.: 0 AF XY: 0.0000154 AC XY: 2 AN XY: 129990

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000278

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000344 AC: 5 AN: 1453300 Hom.: 0 Cov.: 31 AF XY: 0.00000416 AC XY: 3 AN XY: 721774

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000452

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:11

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2A Pathogenic:4

Likely pathogenic, criteria provided, single submitter	research	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Dec 03, 2018	The heterozygous p.Gly445Arg variant in CAPN3 was identified by our study in two unrelated individuals in the compound heterozygous state, with a pathogenic variant, in one individual with limb-girdle muscular dystrophy (LGMD). This variant has been identified in 0.006295% (4/63542) of European (non-Finnish) chromosomes in the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs773827877). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. There are several individuals in the literature with LGMD and this variant in either the compound heterozygous state or with no other known causative variant (PMID: 17994539). In summary, although additional studies are required to fully establish its clinical significance, the clinical significance of the p.Gly445Arg variant is likely pathogenic. ACMG/AMP Criteria applied: PM2, PM3_Strong, PP3 (Richards 2015). -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 16, 2024	This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 445 of the CAPN3 protein (p.Gly445Arg). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individuals with autosomal dominant limb-girdle muscular dystrophy (PMID: 10330340, 15221789, 17236769, 18854869; Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 284515). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CAPN3 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects CAPN3 function (PMID: 15221789, 17236769, 20635405). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, no assertion criteria provided	clinical testing	Counsyl	Jun 02, 2017	- -

not provided Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Nov 03, 2022	The frequency of this variant in the general population is consistent with pathogenicity (http://gnomad.broadinstitute.org). This variant has been seen in multiple individuals with apparently autosomal recessive LGMD (PMID: 10330340, 17994539, 20635405). It has also been reported to segregate with autosomal dominant LGMD in several families (PMID: 32342993). Experiments in patient-derived samples showed absence or significant reduction in CAPN3 protein level/activity in multiple patients. -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Mar 28, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jul 19, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Aug 01, 2023	CAPN3: PP1:Strong, PS1, PM1, PP3, PS3:Supporting -

Muscular dystrophy, limb-girdle, autosomal dominant 4 Pathogenic:2

Pathogenic, flagged submission	clinical testing	Baylor Genetics	Oct 02, 2023	- -
Likely pathogenic, no assertion criteria provided	provider interpretation	Solve-RD Consortium	Jun 01, 2022	Variant confirmed as disease-causing by referring clinical team -

Autosomal recessive limb-girdle muscular dystrophy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Aug 09, 2022

Variant summary: CAPN3 c.1333G>A (p.Gly445Arg) results in a non-conservative amino acid change located in the Peptidase C2, calpain, large subunit, domain III (IPR022682) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 240268 control chromosomes. c.1333G>A has been reported in the literature in multiple individuals affected with Limb-Girdle Muscular Dystrophy, with recent reports associating this variant with an autosomal dominant mode of inheritance (example, Saenz_2005, Avila_2015, Guglieri_2008, Aguennouz_2016, Cerino_2020, Macias_2021). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function demonstrating that the variant impacts calpain-3 catalytic activity and intra/intermolecular autolysis (Cerino_2020). Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	31
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.79	D;.;.;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D;D
M_CAP	Pathogenic	0.81	D
MetaRNN	Pathogenic	1.0	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.8	.;H;.;H
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-7.8	.;D;D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	.;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D
Polyphen		1.0	.;D;D;D
Vest4		0.98
MutPred		0.97		.;Gain of MoRF binding (P = 0.0127);.;Gain of MoRF binding (P = 0.0127);
MVP		0.98
MPC		0.69
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.94
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs773827877; hg19: chr15-42691829;