1-17022724-G-C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_003000.3(SDHB):c.649C>G(p.Arg217Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,204 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R217H) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SDHB
NM_003000.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 7.45

Publications

16 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: Pathogenic. The variant received 18 ACMG points.

PM1

In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 39 uncertain in NM_003000.3

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-17022723-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 412491.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.99

PP5

Variant 1-17022724-G-C is Pathogenic according to our data. Variant chr1-17022724-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 419507.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHB	NM_003000.3 link	c.649C>G	p.Arg217Gly	missense_variant	Exon 7 of 8	ENST00000375499.8	NP_002991.2	P21912
SDHB	NM_001407361.1 link	c.595C>G	p.Arg199Gly	missense_variant	Exon 7 of 8		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8 link	c.649C>G	p.Arg217Gly	missense_variant	Exon 7 of 8	1	NM_003000.3	ENSP00000364649.3		P21912

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000399

AC:

AN:

250790

AF XY:

0.00000737

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000883

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461204

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726894

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:

33460

American (AMR)

AF:

0.00

AC:

AN:

44684

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26116

East Asian (EAS)

AF:

0.00

AC:

AN:

39690

South Asian (SAS)

AF:

0.00

AC:

AN:

86208

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53362

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111562

Other (OTH)

AF:

0.00

AC:

AN:

60358

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.275

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Aug 11, 2025

GeneDx

Significance:Likely pathogenic

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; This variant is associated with the following publications: (PMID: 34906457, 30877234, 19576851, 33726816) -

Pheochromocytoma/paraganglioma syndrome 4

Pathogenic:1

Jan 30, 2024

3billion

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: <0.001%). Predicted Consequence/Location: Missense variant In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.97 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.98 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000419507). The variant has been observed in at least two similarly affected unrelated individuals (PMID: 18753105, 19454582). Different missense changes at the same codon (p.Arg217Cys, p.Arg217His, p.Arg217Leu) have been reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000183735, VCV000412491, VCV000967921 /PMID: 19351833, 19454582, 31492822). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

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

Pathogenic:1

Mar 04, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine with glycine at codon 217 of the SDHB protein (p.Arg217Gly). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and glycine. This variant is present in population databases (rs200245469, ExAC 0.002%). This variant has been reported in an individual affected with clinical features of hereditary paraganglioma-pheochromocytoma syndrome (PMID: 19576851, 30877234). ClinVar contains an entry for this variant (Variation ID: 419507). 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. A different missense substitution at this codon (p.Arg217Cys) has been reported in the literature in many unrelated individuals affected with hereditary pheochromocytoma (PCC) and /or paraganglioma (PGL) (PMID: 18753105, 19351833, 19454582, 19802898, 23735539). This suggests that the arginine residue is critical for SDHB protein function and that other missense substitutions at this position may also be damaging. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.58

BayesDel_noAF

Pathogenic

0.59

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.93

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.99

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Pathogenic

0.99

M_CAP

Pathogenic

0.77

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.6

PhyloP100

7.5

PrimateAI

Pathogenic

0.85

PROVEAN

Pathogenic

-6.1

REVEL

Pathogenic

0.97

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.94

MutPred

0.92

Loss of methylation at R217 (P = 0.0645);

MVP

0.99

MPC

0.79

ClinPred

1.0

GERP RS

5.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.98

gMVP

0.97

Mutation Taster

=3/97

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over