1-17027849-T-C

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate

The NM_003000.3(SDHB):c.440A>G(p.Tyr147Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000709 in 1,607,102 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y147F) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000075 ( 0 hom. )

Consequence

SDHB
NM_003000.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:1

Conservation

PhyloP100: 4.64

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 Likely_pathogenic. Variant got 6 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 13 uncertain in NM_003000.3

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.867

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHB	NM_003000.3 link	c.440A>G	p.Tyr147Cys	missense_variant	Exon 5 of 8	ENST00000375499.8	NP_002991.2	P21912
SDHB	NM_001407361.1 link	c.386A>G	p.Tyr129Cys	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.440A>G	p.Tyr147Cys	missense_variant	Exon 5 of 8	1	NM_003000.3	ENSP00000364649.3		P21912

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152034

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:

0.000386

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000104

AC:

AN:

251178

Hom.:

AF XY:

0.000133

AC XY:

AN XY:

135750

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000173

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000163

Gnomad SAS exome

AF:

0.000392

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000352

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000749

AC:

109

AN:

1455068

Hom.:

Cov.:

AF XY:

0.0000746

AC XY:

AN XY:

724326

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000134

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000383

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000552

Gnomad4 OTH exome

AF:

0.000133

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152034

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74258

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000386

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000480

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.000140

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 15, 2023

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: SDHB c.440A>G (p.Tyr147Cys) results in a non-conservative amino acid change located in the Succinate dehydogenase/fumarate reductase N-terminal domain (IPR025192) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0001 in 251178 control chromosomes in the gnomAD database, including 1 homozygotes. The observed variant frequency is approximately 473 fold of the estimated maximal expected allele frequency for a pathogenic variant in SDHB causing Hereditary Paraganglioma-Pheochromocytoma Syndrome phenotype (2.2e-07), strongly suggesting that the variant is benign. c.440A>G has been reported in the literature in cohorts of individuals affected with Pheochromocytoma and as a VUS in settings of multigene panel testing among individuals with Pheochromocytomas and paragangliomas (PPGLs) (example, Maignan_2017, Pipitprapat_2021) and one report published a REVEL score of 0.87 for this variant (Garrett_2022). These report(s) do not provide unequivocal conclusions about association of the variant with Hereditary Paraganglioma-Pheochromocytoma Syndrome. The following publications have been ascertained in the context of this evaluation (PMID: 28229225, 34309460, 34906457). Five submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as VUS (n=4) or likely benign (n=1). Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -

Pheochromocytoma

Uncertain:1

Aug 24, 2019

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Gastrointestinal stromal tumor;C1847319:Carney-Stratakis syndrome;C1861848:Paragangliomas 4;C5543176:Mitochondrial complex 2 deficiency, nuclear type 4

Uncertain:1

Aug 26, 2024

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Uncertain:1

Jan 29, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 147 of the SDHB protein (p.Tyr147Cys). This variant is present in population databases (rs774568101, gnomAD 0.04%). This missense change has been observed in individual(s) with clinical features of SDHB-related conditions (PMID: 28229225, 34309460; internal data). ClinVar contains an entry for this variant (Variation ID: 412466). 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 have shown that this missense change affects SDHB function (PMID: 28229225). 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. -

not provided

Uncertain:1

May 26, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Published functional studies demonstrate that this variant may disrupt SDH cellular compartmentalization (Maignan et al., 2017); Observed in individuals with pheochromocytoma or paraganglioma (Maignan et al., 2017; Garrett et al., 2022); This variant is associated with the following publications: (PMID: 28229225, 34426522, 34906457) -

Gastrointestinal stromal tumor

Uncertain:1

Dec 24, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cowden syndrome

Uncertain:1

Jul 02, 2018

Mendelics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary pheochromocytoma-paraganglioma

Uncertain:1

Mar 24, 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 tyrosine with cysteine at codon 147 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 have shown that this variant results in decreased SDHB mitochondrial membrane localization, and reduced SDH activity (PMID: 28229225). This variant has been reported in individuals affected with paraganglioma (PGL) or pheochromocytoma (PCC) in the literature (PMID: 28229225, 34309460, 34906457). This variant has been identified in 26/251178 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. -

Hereditary cancer-predisposing syndrome

Benign:1

Sep 21, 2021

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.70

BayesDel_addAF

Pathogenic

0.30

BayesDel_noAF

Pathogenic

0.52

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.93

D;.;D

Eigen

Pathogenic

0.84

Eigen_PC

Pathogenic

0.71

FATHMM_MKL

Uncertain

0.94

LIST_S2

Pathogenic

0.99

D;D;D

M_CAP

Pathogenic

0.57

MetaRNN

Pathogenic

0.87

D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

4.6

H;.;.

PrimateAI

Pathogenic

0.80

PROVEAN

Pathogenic

-8.0

D;.;.

REVEL

Pathogenic

0.87

Sift

Pathogenic

0.0

D;.;.

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;.;.

Vest4

0.89

MutPred

0.63

Loss of ubiquitination at K151 (P = 0.0464);.;.;

MVP

0.99

MPC

0.77

ClinPred

1.0

GERP RS

4.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.96

gMVP

0.91

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