chr12-57243911-C-G

Position:

• chr12-57243911-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_145064.3(STAC3):​c.997-1G>C variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,454 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: STAC3 NM_145064.3 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.44

Genes affected

STAC3 (HGNC:28423): (SH3 and cysteine rich domain 3) The protein encoded by this gene is a component of the excitation-contraction coupling machinery of muscles. This protein is a member of the Stac gene family and contains an N-terminal cysteine-rich domain and two SH3 domains. Mutations in this gene are a cause of Native American myopathy. [provided by RefSeq, Nov 2013]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.41278538 fraction of the gene.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
STAC3	NM_145064.3	c.997-1G>C		splice_acceptor_variant		ENST00000332782.7	NP_659501.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
STAC3	ENST00000332782.7	c.997-1G>C		splice_acceptor_variant		2	NM_145064.3	ENSP00000329200	P1
STAC3	ENST00000554578.5	c.880-1G>C		splice_acceptor_variant		1		ENSP00000452068
STAC3	ENST00000557176.5	c.*57-1G>C		splice_acceptor_variant, NMD_transcript_variant		1		ENSP00000450740
STAC3	ENST00000546246.2	c.439-1G>C		splice_acceptor_variant		2		ENSP00000441515

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461454 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 726988

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bailey-Bloch congenital myopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 14, 2021

This sequence change falls in intron 11 of the STAC3 gene. It does not directly change the encoded amino acid sequence of the STAC3 protein. It affects a nucleotide within the consensus splice site of the intron. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with STAC3-related conditions. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). 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 available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.33
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Uncertain	0.91	D
MutationTaster	Benign	1.0	D;D;D
GERP RS		4.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.77		Position offset: -13
DS_AL_spliceai		0.98		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: rs779483367; hg19: chr12-57637694;