chr15-42394343-T-C

Variant names:

• chr15-42394343-T-C
• rs1057524468
• NM_000070.3:c.1115+2T>C

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000070.3(CAPN3):​c.1115+2T>C variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CAPN3 NM_000070.3 splice_donor, intron
• Scores: Splicing: ADA: 0.9928
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 7.38
• Publications: 1 publications found

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]

CAPN3 Gene-Disease associations (from GenCC):

• autosomal recessive limb-girdle muscular dystrophy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• autosomal recessive limb-girdle muscular dystrophy type 2A

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Myriad Women’s Health, Labcorp Genetics (formerly Invitae)
• muscular dystrophy, limb-girdle, autosomal dominant 4

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• muscular dystrophy, limb-girdle, autosomal dominant

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ENSG00000258461 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 10, offset of 4, new splice context is: cagGTgagg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-42394343-T-C is Pathogenic according to our data. Variant chr15-42394343-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 392385.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000070.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CAPN3	NM_000070.3	MANE Select	c.1115+2T>C		splice_donor intron	N/A	NP_000061.1
	CAPN3	NM_024344.2		c.1115+2T>C		splice_donor intron	N/A	NP_077320.1
	CAPN3	NM_173087.2		c.971+2T>C		splice_donor intron	N/A	NP_775110.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CAPN3	ENST00000397163.8	TSL:1 MANE Select	c.1115+2T>C		splice_donor intron	N/A	ENSP00000380349.3
	CAPN3	ENST00000357568.8	TSL:1	c.1115+2T>C		splice_donor intron	N/A	ENSP00000350181.3
	CAPN3	ENST00000349748.8	TSL:1	c.971+2T>C		splice_donor intron	N/A	ENSP00000183936.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2A Pathogenic:3

Oct 07, 2024

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is not observed in the gnomAD v4.1.0 dataset. Predicted Consequence/Location: Canonical splice site: predicted to alter splicing and result in a loss or disruption of normal protein function. Multiple pathogenic loss-of-function variants are reported downstream of the variant. The variant has been reported at least twice as pathogenic without evidence for the classification (ClinVar ID: VCV000392385 /3billion dataset). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline.

Mar 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 8 of the CAPN3 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CAPN3 are known to be pathogenic (PMID: 10330340, 15689361). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CAPN3-related conditions. ClinVar contains an entry for this variant (Variation ID: 392385). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic.

Jul 17, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with autosomal recessive limb-girdle muscular dystrophy 1 (MIM#253600). Dominant-negative is the suggested mechanism for autosomal dominant limb-girdle muscular dystrophy 4 (MIM#618129; PMIDs: 27259757, 28881388). (I) 0108 - This gene is associated with both recessive and dominant disease. Autosomal dominant limb-girdle muscular dystrophy is associated with milder presentation and later onset (PMID: 32342993). (I) 0211 - Canonical splice site variant without proven consequence on splicing (no functional evidence available). (SP) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0505 - Abnormal splicing is predicted by in silico tools and affected nucleotide is highly conserved. (SP) 0702 - Other splice site variants comparable to the one identified in this case have strong previous evidence for pathogenicity. At least three other variants inthis splice region, c.1115+1G>A, c.1115+2T>A and c.1115+5G>C, have been reported in affected individuals (Clinvar, PMID: 32646536). (SP) 0803 - This variant has limited previous evidence of pathogenicity in an unrelated individual. It has been classified as pathogenic by a diagnostic laboratory in ClinVar. (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1101 - Very strong and specific phenotype match for this individual. (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign

Muscular dystrophy, limb-girdle, autosomal dominant 4 Pathogenic:1

Oct 03, 2023

Baylor Genetics

Significance: Likely pathogenic

Review Status: flagged submission

Collection Method: clinical testing

not provided Pathogenic:1

Jan 04, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1115+2 T>C pathogenic variant in the CAPN3 gene destroys the canonical splice donor site in intron 8. It is predicted to cause abnormal gene splicing, either leading to an abnormal message that is subject to nonsense-mediated mRNA decay, or to an abnormal protein product if the message is used for protein translation. The c.1115+2 T>C variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). Although the c.1115+2 T>C variant has not been published to our knowledge, other splice site variants in the CAPN3 gene have been reported in the Human Gene Mutation Database in association with limb-girdle muscular dystrophy (Stenson et al., 2014).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.4
GERP RS		5.3
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Benign	0.72
SpliceAI score (max)		0.87		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.51		Position offset: 2
DS_DL_spliceai		0.87		Position offset: -2

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

Other links and lift over

dbSNP: rs1057524468; hg19: chr15-42686541;