1-17023978-T-C

Position:

• chr1-17023978-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_003000.3(SDHB):​c.637A>G​(p.Met213Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,457,406 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SDHB NM_003000.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.14

Genes affected

SDHB (HGNC:10681): (succinate dehydrogenase complex iron sulfur subunit B) This tumor suppressor gene encodes the iron-sulfur protein subunit of the succinate dehydrogenase (SDH) enzyme complex which plays a critical role in mitochondria. The SDH enzyme complex is composed of four nuclear-encoded subunits. This enzyme complex converts succinate to fumarate which releases electrons as part of the citric acid cycle, and the enzyme complex additionally provides an attachment site for released electrons to be transferred to the oxidative phosphorylation pathway. The SDH enzyme complex plays a role in oxygen-related gene regulation through its conversion of succinate, which is an oxygen sensor that stabilizes the hypoxia-inducible factor 1 (HIF1) transcription factor. Sporadic and familial mutations in this gene result in paragangliomas, pheochromocytoma, and gastrointestinal stromal tumors, supporting a link between mitochondrial dysfunction and tumorigenesis. Mutations in this gene are also implicated in nuclear type 4 mitochondrial complex II deficiency. [provided by RefSeq, Jun 2022]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a region_of_interest Interaction with SDHAF1 (size 72) in uniprot entity SDHB_HUMAN there are 30 pathogenic changes around while only 1 benign (97%) in NM_003000.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.894

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SDHB	NM_003000.3	c.637A>G	p.Met213Val	missense_variant	6/8	ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1	c.583A>G	p.Met195Val	missense_variant	6/8		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8	c.637A>G	p.Met213Val	missense_variant	6/8	1	NM_003000.3	ENSP00000364649	P1
SDHB	ENST00000491274.6	c.595A>G	p.Met199Val	missense_variant	6/8	5		ENSP00000480482
SDHB	ENST00000463045.3	c.466A>G	p.Met156Val	missense_variant	6/8	3		ENSP00000481376
SDHB	ENST00000485515.5	n.571A>G		non_coding_transcript_exon_variant	6/7	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1457406 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 725200

Gnomad4 AFR exome AF: 0.0000300

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: 9.02e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Pheochromocytoma;C0238198:Gastrointestinal stromal tumor;C1861848:Paragangliomas 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 10, 2023

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SDHB protein function. ClinVar contains an entry for this variant (Variation ID: 412486). This variant has not been reported in the literature in individuals affected with SDHB-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 213 of the SDHB protein (p.Met213Val). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 26, 2023

The p.M213V variant (also known as c.637A>G), located in coding exon 6 of the SDHB gene, results from an A to G substitution at nucleotide position 637. The methionine at codon 213 is replaced by valine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.56
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	D;.
Eigen	Uncertain	0.68
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.89	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	1.8	L;.
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-3.3	D;.
REVEL	Pathogenic	0.89
Sift	Uncertain	0.0010	D;.
Sift4G	Uncertain	0.0020	D;D
Polyphen		0.99	D;.
Vest4		0.88
MutPred		0.55		Gain of catalytic residue at M213 (P = 0.0439);.;
MVP		0.99
MPC		0.62
ClinPred		0.98	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.71
gMVP		0.88

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs770622939; hg19: chr1-17350473;