rs1555420507

chr15-42387890-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3 PP5

The NM_000070.3(CAPN3):c.632+4A>G variant causes a splice donor region, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CAPN3 NM_000070.3 splice_donor_region, intron
• Scores: Splicing: ADA: 0.9977
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 6.24

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 Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 15-42387890-A-G is Pathogenic according to our data. Variant chr15-42387890-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 550589.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=2, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CAPN3	NM_000070.3	c.632+4A>G		splice_donor_region_variant, intron_variant		ENST00000397163.8
CAPN3	NM_024344.2	c.632+4A>G		splice_donor_region_variant, intron_variant
CAPN3	NM_173087.2	c.632+4A>G		splice_donor_region_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CAPN3	ENST00000397163.8	c.632+4A>G		splice_donor_region_variant, intron_variant		1	NM_000070.3	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2A Pathogenic:1 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	May 27, 2022	For these reasons, this variant has been classified as Pathogenic. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in exon 4 skipping and introduces a premature termination codon (PMID: 18563459). The resulting mRNA is expected to undergo nonsense-mediated decay. ClinVar contains an entry for this variant (Variation ID: 550589). This variant is also known as IVS4+4A>G. This variant has been observed in individual(s) with autosomal recessive limb-girdle muscular dystrophy (PMID: 18563459, 33335567). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 4 of the CAPN3 gene. It does not directly change the encoded amino acid sequence of the CAPN3 protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or disrupted protein product. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Feb 07, 2017	- -

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

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Apr 02, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.18
Cadd	Benign	20
Dann	Uncertain	0.98

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.56		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.56		Position offset: -4

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555420507; hg19: chr15-42680088;