5-225879-ACAG-A

Position:

chr5-225879-ACAG-A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_ModeratePM2PP3_ModeratePP5_Very_Strong

The NM_004168.4(SDHA):c.457-2_457del variant causes a splice acceptor, splice polypyrimidine tract, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,172 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 Pathogenic (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

SDHA
NM_004168.4 splice_acceptor, splice_polypyrimidine_tract, intron

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 9.48

Variant links:

Genes affected

SDHA (HGNC:10680): (succinate dehydrogenase complex flavoprotein subunit A) This gene encodes a major catalytic subunit of succinate-ubiquinone oxidoreductase, a complex of the mitochondrial respiratory chain. The complex is composed of four nuclear-encoded subunits and is localized in the mitochondrial inner membrane. Mutations in this gene have been associated with a form of mitochondrial respiratory chain deficiency known as Leigh Syndrome. A pseudogene has been identified on chromosome 3q29. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jun 2014]

SDHA links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 14 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.08220551 fraction of the gene. Cryptic splice site detected, with MaxEntScore 8.7, offset of 1, new splice context is: ttgtttttatctttcactAGaaa. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

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 5-225879-ACAG-A is Pathogenic according to our data. Variant chr5-225879-ACAG-A is described in ClinVar as [Pathogenic]. Clinvar id is 239672.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SDHA	NM_004168.4 linkuse as main transcript	c.457-2_457del		splice_acceptor_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000264932.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SDHA	ENST00000264932.11 linkuse as main transcript	c.457-2_457del		splice_acceptor_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_004168.4	P1	P31040-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

6.85e-7

AC:

AN:

1460212

Hom.:

AF XY:

0.00

AC XY:

AN XY:

726454

show subpopulations

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:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74334

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Paragangliomas 5;C5700310:Mitochondrial complex II deficiency, nuclear type 1

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Sep 03, 2023

This sequence change affects a splice site in intron 4 of the SDHA 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 SDHA are known to be pathogenic (PMID: 22974104, 24781757). For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 239672). This variant is also known as c.457-3_457-1delCAG. Disruption of this splice site has been observed in individuals with gastrointestinal stromal tumor (GIST) (PMID: 23109135, 23612575; Invitae). This variant is not present in population databases (gnomAD no frequency). -

Dilated cardiomyopathy 1GG

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Nov 12, 2023

- -

Gastrointestinal stromal tumor

Pathogenic:1

Pathogenic, criteria provided, single submitter

research

“Giorgio Prodi” Cancer Research Center, University of Bologna

Oct 01, 2021

- -

Hereditary cancer-predisposing syndrome

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 18, 2021

The c.457-2_457delAGC pathogenic mutation results from a deletion of AGC nucleotides between positions 457-2 and 457 and involves the canonical splice acceptor site before coding exon 5 of the SDHA gene. This mutation (also designated as c.457-3_457-1delCAG) has been reported as germline in individuals with gastrointestinal stromal tumors (GISTs) that demonstrated absent SDHB staining by IHC (Belinsky MG et al. Genes Chromosomes Cancer 2013 02;52(2):214-24; Pantaleo MA et al. Eur J Hum Genet 2014 Jan;22(1):32-9). In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site and will result in the creation or strengthening of a novel splice acceptor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.81

Position offset: 8

DS_AL_spliceai

1.0

Position offset: 4

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over