NM_003000.3:c.724C>A

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.724C>A(p.Arg242Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,774 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R242C) 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 criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 7.48

Publications

13 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 2 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 chr1-17022649-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 186827.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.986

PP5

Variant 1-17022649-G-T is Pathogenic according to our data. Variant chr1-17022649-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 239443.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.724C>A	p.Arg242Ser	missense_variant	Exon 7 of 8	ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1 link	c.670C>A	p.Arg224Ser	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.724C>A	p.Arg242Ser	missense_variant	Exon 7 of 8	1	NM_003000.3	ENSP00000364649.3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461774

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727196

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:

33476

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.00

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53404

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111946

Other (OTH)

AF:

0.00

AC:

AN:

60388

⚠️ 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: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hereditary pheochromocytoma-paraganglioma

Pathogenic:3

Nov 17, 2024

Color Diagnostics, LLC DBA Color Health

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces arginine with serine at codon 242 of the SDHB protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function. Functional studies in yeast have shown that this variant signifiantly affected SDH activity and mitochondrial respiration, increasing of mtDNA mutability and sensitivity to oxidative stress. The variant disrupts a functionally important LYR motif. (PMID: 23175444, 26719882). This variant has been reported in individuals affected with paragangliomas and/or pheochromocytomas (PMID: 19351833, 34377882, 34906457, 35870552). Different missense variants at this position, p.Arg242Cys and p.Arg242His, are considered disease-causing (ClinVar Variation ID: VCV000012781, VCV000186827). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Pathogenic.

Sep 28, 2024

All of Us Research Program, National Institutes of Health

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces arginine with serine at codon 242 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). Functional studies in yeast have shown that this variant signifiantly affected SDH activity and mitochondrial respiration, increasing of mtDNA mutability and sensitivity to oxidative stress. The variant disrupts a functionally important LYR motif. (PMID: 23175444, 26719882). This variant has been reported in individuals affected with paragangliomas and/or pheochromocytomas (PMID: 19351833, 34377882, 34906457, 35870552). Other variants at this position are considered disease causing (ClinVar Variation ID: VCV000012781, VCV000186827). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Pathogenic.

Jul 17, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: SDHB c.724C>A (p.Arg242Ser) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251440 control chromosomes. c.724C>A has been reported in the literature in individuals affected with Hereditary Paraganglioma-Pheochromocytoma Syndrome (e.g. Neumann_2009, Siddiqui_2021, Garrett_2022). These data indicate that the variant is likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in undetectable SDH enzyme activity in vitro (e.g. Panizza_2013). The following publications have been ascertained in the context of this evaluation (PMID: 34906457, 19351833, 23175444, 34377882). Three submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic.

not provided

Pathogenic:1

Feb 15, 2024

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Published functional studies demonstrate a damaging effect: defective SDH enzyme activity and increased mtDNA mutability and sensitivity to oxidative stress (PMID: 23175444); 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: 25972245, 19351833, 22904323, 30787465, 31492822, 34377882, 34906457, 23175444)

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

Pathogenic:1

Jul 21, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 242 of the SDHB protein (p.Arg242Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with paraganglioma (PMID: 19351833; Invitae). ClinVar contains an entry for this variant (Variation ID: 239443). 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 not expected to disrupt SDHB protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects SDHB function (PMID: 23175444). This variant disrupts the p.Arg242 amino acid residue in SDHB. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19351833, 21173220, 22517554). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic.

Hereditary cancer-predisposing syndrome

Pathogenic:1

Mar 22, 2024

Ambry Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.R242S pathogenic mutation (also known as c.724C>A), located in coding exon 7 of the SDHB gene, results from a C to A substitution at nucleotide position 724. The arginine at codon 242 is replaced by serine, an amino acid with dissimilar properties. This alteration was reported in 2/578 individuals with head and neck paragangliomas (Neumann HP et al. Cancer Res. 2009 Apr;69(8):3650-6). In addition, a different disease causing mutation, p.R242H, has been described at this position (Kim E et al. Endocr. Relat. Cancer. 2015 Jun; 22(3):387-97). Functional studies using yeast models determined that the yeast-equivalent alteration of p.R242S, yR235S, results in an OXPHOS phenotype similar to the null strain; with no detectable SDH activity, 50% reduction in respiration, and increased genomic instability (Panizza E et al. Hum. Mol. Genet. 2013 Feb;22(4):804-15). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as a pathogenic mutation.

SDHB-related disorder

Pathogenic:1

Apr 05, 2024

PreventionGenetics, part of Exact Sciences

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

The SDHB c.724C>A variant is predicted to result in the amino acid substitution p.Arg242Ser. This variant has been repeatedly reported in individuals with paraganglioma (see for example, Neumann et al. 2009. PubMed ID: 19351833, Suppl. Table 1; Panizza et al. 2012. PubMed ID: 23175444; Siddiqui et al. 2021. PubMed ID: 34377882; Garrett et al. 2021. PubMed ID: 34906457, Supplementary Table 2). In the Panizza et al. study, the yeast model study showed that this missense change has a severe phenotypic effect. This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. In ClinVar, this variant has been widely interpreted as pathogenic (https://preview.ncbi.nlm.nih.gov/clinvar/variation/239443/). This variant is interpreted as pathogenic.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.55

BayesDel_noAF

Pathogenic

0.56

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.80

Eigen

Pathogenic

0.94

Eigen_PC

Pathogenic

0.92

LIST_S2

Pathogenic

0.98

M_CAP

Pathogenic

0.69

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.7

PhyloP100

7.5

PrimateAI

Uncertain

0.79

PROVEAN

Pathogenic

-4.6

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Vest4

0.88

ClinPred

1.0

GERP RS

5.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.93

gMVP

0.94

Mutation Taster

=9/91

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