1-17027766-C-G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PM2

The NM_003000.3(SDHB):c.523G>C(p.Glu175Gln) variant causes a missense change. The variant allele was found at a frequency of 0.00000125 in 1,598,188 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. E175K) has been classified as Uncertain significance.

Frequency

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

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

SDHB
NM_003000.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 4.52

Publications

1 publications found

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 Gene-Disease associations (from GenCC):

Carney-Stratakis syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, G2P, Orphanet
gastrointestinal stromal tumor
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
hereditary pheochromocytoma-paraganglioma
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
pheochromocytoma
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
pheochromocytoma/paraganglioma syndrome 4
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae)
mitochondrial disease
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
renal cell carcinoma
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
mitochondrial complex 2 deficiency, nuclear type 4
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
Cowden disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
mitochondrial complex II deficiency
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

SDHB links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM1

In a region_of_interest Interaction with SDHAF1 (size 72) in uniprot entity SDHB_HUMAN there are 37 pathogenic changes around while only 2 benign (95%) in NM_003000.3

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHB	NM_003000.3 link	c.523G>C	p.Glu175Gln	missense_variant	Exon 5 of 8	ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1 link	c.469G>C	p.Glu157Gln	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.523G>C	p.Glu175Gln	missense_variant	Exon 5 of 8	1	NM_003000.3	ENSP00000364649.3

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152206

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

AF:

6.92e-7

AC:

AN:

1445982

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

720406

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33140

American (AMR)

AF:

0.00

AC:

AN:

44706

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26032

East Asian (EAS)

AF:

0.00

AC:

AN:

39642

South Asian (SAS)

AF:

0.00

AC:

AN:

85914

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53344

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5728

European-Non Finnish (NFE)

AF:

9.11e-7

AC:

AN:

1097644

Other (OTH)

AF:

0.00

AC:

AN:

59832

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152206

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74352

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41460

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000340

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:2

Dec 23, 2021

Sema4, Sema4

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:curation

- -

May 25, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.E175Q variant (also known as c.523G>C), located in coding exon 5 of the SDHB gene, results from a G to C substitution at nucleotide position 523. The glutamic acid at codon 175 is replaced by glutamine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Mar 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

SDHB: PM2 -

Pheochromocytoma;C0238198:Gastrointestinal stromal tumor;C1861848:Pheochromocytoma/paraganglioma syndrome 4

Uncertain:1

Jan 13, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 175 of the SDHB protein (p.Glu175Gln). This variant is present in population databases (rs202203339, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with SDHB-related conditions. ClinVar contains an entry for this variant (Variation ID: 528731). 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 not expected to disrupt SDHB protein function with a negative predictive value of 80%. 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. -

Hereditary pheochromocytoma-paraganglioma

Uncertain:1

Dec 01, 2023

All of Us Research Program, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.10

BayesDel_addAF

Pathogenic

0.20

BayesDel_noAF

Uncertain

0.040

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.50

T;.;T

Eigen

Uncertain

0.20

Eigen_PC

Uncertain

0.36

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.92

D;D;D

M_CAP

Uncertain

0.13

MetaRNN

Uncertain

0.53

D;D;D

MetaSVM

Uncertain

0.71

MutationAssessor

Uncertain

2.5

M;.;.

PhyloP100

4.5

PrimateAI

Uncertain

0.49

PROVEAN

Benign

-1.9

N;.;.

REVEL

Uncertain

0.47

Sift

Uncertain

0.019

D;.;.

Sift4G

Benign

0.063

T;T;D

Polyphen

0.018

B;.;.

Vest4

0.38

MutPred

0.35

Loss of ubiquitination at K179 (P = 0.0949);.;.;

MVP

0.94

MPC

0.17

ClinPred

0.87

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.29

gMVP

0.77

Mutation Taster

=47/53

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.22

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.22

Position offset: -6

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over