1-17027759-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM2PP3

The NM_003000.3(SDHB):c.530G>A(p.Arg177His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000177 in 1,584,548 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R177C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000015 ( 0 hom. )

Consequence

SDHB
NM_003000.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:9

Conservation

PhyloP100: 7.37

Variant links:

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]

SDHB links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 16 uncertain in NM_003000.3

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.806

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHB	NM_003000.3 link	c.530G>A	p.Arg177His	missense_variant	Exon 5 of 8	ENST00000375499.8	NP_002991.2	P21912
SDHB	NM_001407361.1 link	c.476G>A	p.Arg159His	missense_variant	Exon 5 of 8		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8 link	c.530G>A	p.Arg177His	missense_variant	Exon 5 of 8	1	NM_003000.3	ENSP00000364649.3		P21912

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152188

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000327

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000318

AC:

AN:

251384

Hom.:

AF XY:

0.0000515

AC XY:

AN XY:

135876

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.0000154

AC:

AN:

1432242

Hom.:

Cov.:

AF XY:

0.0000210

AC XY:

AN XY:

714332

show subpopulations

Gnomad4 AFR exome

AF:

0.0000913

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000505

Gnomad4 SAS exome

AF:

0.0000234

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000922

Gnomad4 OTH exome

AF:

0.0000337

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152306

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74470

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.000327

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000772

Hom.:

Bravo

AF:

0.0000907

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:9

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Jul 13, 2023

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 22, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Published functional studies in yeast demonstrate mild impact on SDH activity (Panizza et al., 2013); Observed in individuals with a personal and/or family history of head and neck paraganglioma (Michalowska et al., 2016; Bayley et al., 2020; Richter et al., 2022); Also known as p.R149H; This variant is associated with the following publications: (PMID: 25720320, 25791839, 27867439, 27967220, 31492822, 33152312, 23175444, 25595276, 35171114) -

Hereditary cancer-predisposing syndrome

Uncertain:2

Dec 16, 2021

Sema4, Sema4

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Sep 28, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R177H variant (also known as c.530G>A), located in coding exon 5 of the SDHB gene, results from a G to A substitution at nucleotide position 530. The arginine at codon 177 is replaced by histidine, an amino acid with highly similar properties. This variant has been reported in multiple individuals diagnosed with paraganglioma or pheochromocytoma, and segregated with disease in one family (von Dobschuetz E et al. Endocr. Relat. Cancer. 2015 Apr;22:191-204; Michaowska I et al. Neuroendocrinology. 2015 Mar;101:321-30; Richter S et al. Endocr Relat Cancer, 2022 Mar;29:213-224); however, this alteration has also been observed in several apparently healthy individuals (Rana HQ et al. Cancers (Basel), 2024 Feb;16; Ambry internal data). Functional studies of this variant demonstrate only a mildly impaired phenotype using a yeast model (Panizza E et al. Hum. Mol. Genet. 2013 Feb;22:804-15). 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 and conflicting at this time, the clinical significance of this alteration remains unclear. -

not specified

Uncertain:1

Mar 13, 2019

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Uncertain:1

Jan 21, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 177 of the SDHB protein (p.Arg177His). This variant is present in population databases (rs150437793, gnomAD 0.006%). This missense change has been observed in individual(s) with paraganglioma-pheochromocytoma (PGL-PCC) syndrome as well as in unaffected individuals (PMID: 25595276, 27867439, 31492822, 35171114; internal data). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 239433). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt SDHB protein function with a positive predictive value of 80%. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on SDHB function (PMID: 23175444). RNA analysis performed to evaluate the impact of this missense change on mRNA splicing indicates it does not significantly alter 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. -

Paragangliomas 4

Uncertain:1

Feb 05, 2025

St. Jude Molecular Pathology, St. Jude Children's Research Hospital

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The SDHB c.530G>A (p.Arg177His) missense change has a maximum frequency of 0.006% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/). The in silico tool REVEL predicts a deleterious effect on protein function, and a functional study in yeast demonstrated a mild impact on succinate dehydrogenase function (PMID: 23175444). This variant has been reported in individuals with paragangliomas and pheochromocytomas and was found to segregate in one family (PMID: 25595276, 25791839, 27867439, 35171114). In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -

Gastrointestinal stromal tumor

Uncertain:1

Aug 25, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary pheochromocytoma-paraganglioma

Uncertain:1

Sep 27, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with histidine at codon 177 of the SDHB protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). An experimental functional study in a yeast model demonstrated partial impacts on succinate dehydrogenase function (PMID: 23175444). This variant has been reported in individuals affected with paragangliomas and pheochromocytomas (PMID: 25595276, 25791839, 27867439, 35171114), but also in unaffected individuals (PMID: 25595276, 27867439). The variant has been observed to segregate in one family (PMID: 25595276). This variant has been identified in 8/251384 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.91

BayesDel_addAF

Pathogenic

0.31

BayesDel_noAF

Pathogenic

0.38

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.70

D;.;D

Eigen

Uncertain

0.61

Eigen_PC

Uncertain

0.60

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Uncertain

0.93

D;D;D

M_CAP

Pathogenic

0.40

MetaRNN

Pathogenic

0.81

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.0

H;.;.

PrimateAI

Uncertain

0.67

PROVEAN

Uncertain

-4.2

D;.;.

REVEL

Pathogenic

0.80

Sift

Pathogenic

0.0

D;.;.

Sift4G

Uncertain

0.0070

D;D;D

Polyphen

0.61

P;.;.

Vest4

0.79

MVP

0.98

MPC

0.60

ClinPred

1.0

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.91

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

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