dbSNP rs375280597: SDHAF2:c.371-2A>G (chr11-61445939-A-G) – ACMG Classification: Uncertain_significance (5 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 9P and 4B. PVS1PP5BS2

The NM_017841.4(SDHAF2):c.371-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000287 in 1,461,856 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.000029 ( 0 hom. )

Consequence

SDHAF2
NM_017841.4 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1

Conservation

PhyloP100: 8.06

Variant links:

Genes affected

SDHAF2 (HGNC:26034): (succinate dehydrogenase complex assembly factor 2) This gene encodes a mitochondrial assembly factor needed for the flavination of a succinate dehydrogenase complex subunit (SDHA), which is required for activity of the succinate dehydrogenase complex. Mutations in this gene are associated with paraganglioma. [provided by RefSeq, May 2022]

SDHAF2 links:

ENSG00000256591 (HGNC:):

ENSG00000256591 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PP5

Variant 11-61445939-A-G is Pathogenic according to our data. Variant chr11-61445939-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 411604.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=1}.

BS2

High AC in GnomAdExome4 at 42 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHAF2	NM_017841.4 link	c.371-2A>G		splice_acceptor_variant, intron_variant	Intron 3 of 3	ENST00000301761.7	NP_060311.1	Q9NX18

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHAF2	ENST00000301761.7 link	c.371-2A>G		splice_acceptor_variant, intron_variant	Intron 3 of 3	1	NM_017841.4	ENSP00000301761.3		Q9NX18
ENSG00000256591	ENST00000541135.5 link	c.377+7819A>G		intron_variant	Intron 3 of 4	4		ENSP00000443130.1		F5H5T6

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251338

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135862

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000287

AC:

AN:

1461856

Hom.:

Cov.:

AF XY:

0.0000234

AC XY:

AN XY:

727230

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:

0.0000378

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000489

Hom.:

Bravo

AF:

0.0000227

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000233

AC:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Paragangliomas 2

Pathogenic:1

Apr 25, 2022

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome

Pathogenic:1

Jun 03, 2024

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.371-2A>G intronic variant results from an A to G substitution two nucleotides upstream from coding exon 4 in the SDHAF2 gene. This alteration occurs at the 3' terminus of the SDHAF2 gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 43 amino acids of the protein. The exact functional effect of this alteration is unknown; however, the impacted region is critical for protein function and a significant portion of the protein is affected (Ambry internal data). This alteration has been observed in at least one individual with a personal history that is consistent with SDHAF2-related disease (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site; however, direct evidence is insufficient at this time (Ambry internal data). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Hereditary pheochromocytoma-paraganglioma

Uncertain:1

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects an acceptor splice site in intron 3 of the SDHAF2 gene. While this variant is not anticipated to result in nonsense mediated decay, it likely alters RNA splicing and results in a disrupted protein product. This variant is present in population databases (rs375280597, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with SDHAF2-related conditions. ClinVar contains an entry for this variant (Variation ID: 411604). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that disruption of this splice site is associated with inconclusive levels of altered splicing (internal data). 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

0.55

BayesDel_noAF

Pathogenic

0.37

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.95

FATHMM_MKL

Pathogenic

0.99

GERP RS

5.4

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.96

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.96

Position offset: 2

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