rs1553537332

chr2-71539238-AG-A

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PVS1 PM2 PP3_Moderate PP5_Very_Strong

The NM_001130987.2(DYSF):c.1576+1del variant causes a frameshift, splice region change. The variant allele was found at a frequency of 0.000000684 in 1,461,448 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. VDDY526?) has been classified as Likely pathogenic. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: DYSF NM_001130987.2 frameshift, splice_region
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.03

Genes affected

DYSF (HGNC:3097): (dysferlin) The protein encoded by this gene belongs to the ferlin family and is a skeletal muscle protein found associated with the sarcolemma. It is involved in muscle contraction and contains C2 domains that play a role in calcium-mediated membrane fusion events, suggesting that it may be involved in membrane regeneration and repair. In addition, the protein encoded by this gene binds caveolin-3, a skeletal muscle membrane protein which is important in the formation of caveolae. Specific mutations in this gene have been shown to cause autosomal recessive limb girdle muscular dystrophy type 2B (LGMD2B) as well as Miyoshi myopathy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2008]

ACMG classification

Verdict is Pathogenic. Variant got 20 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 2-71539238-AG-A is Pathogenic according to our data. Variant chr2-71539238-AG-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 552948.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-71539238-AG-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
DYSF	NM_001130987.2	c.1576+1del		frameshift_variant, splice_region_variant	17/56	ENST00000410020.8
DYSF	NM_003494.4	c.1480+1del		frameshift_variant, splice_region_variant	16/55	ENST00000258104.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
DYSF	ENST00000410020.8	c.1576+1del		frameshift_variant, splice_region_variant	17/56	1	NM_001130987.2	A1
DYSF	ENST00000258104.8	c.1480+1del		frameshift_variant, splice_region_variant	16/55	1	NM_003494.4	A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461448 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727066

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Jul 19, 2017

- -

Miyoshi muscular dystrophy 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Sep 05, 2023

- -

Qualitative or quantitative defects of dysferlin Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Apr 11, 2022

This sequence change creates a premature translational stop signal (p.Glu494Argfs*133) in the DYSF gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in DYSF are known to be pathogenic (PMID: 17698709, 20301480). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with Miyoshi myopathy (PMID: 16996541). This variant is also known as c.1481+1delG. ClinVar contains an entry for this variant (Variation ID: 552948). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.65		Position offset: 0
DS_DL_spliceai		0.99		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553537332; hg19: chr2-71766368;