1-17027760-G-A

Position:

chr1-17027760-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1PM2PM5PP3_Moderate

The NM_003000.3(SDHB):c.529C>T(p.Arg177Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000631 in 1,584,240 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. R177H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000049 ( 0 hom. )

Consequence

SDHB
NM_003000.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 4.72

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 8 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;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-17027759-C-T is described in Lovd as [Likely_pathogenic].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.925

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SDHB	NM_003000.3 linkuse as main transcript	c.529C>T	p.Arg177Cys	missense_variant	5/8	ENST00000375499.8
SDHB	NM_001407361.1 linkuse as main transcript	c.475C>T	p.Arg159Cys	missense_variant	5/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SDHB	ENST00000375499.8 linkuse as main transcript	c.529C>T	p.Arg177Cys	missense_variant	5/8	1	NM_003000.3	P1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152130

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

251376

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135874

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000489

AC:

AN:

1432110

Hom.:

Cov.:

AF XY:

0.00000560

AC XY:

AN XY:

714294

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000117

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000553

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152130

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74310

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.0000302

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jun 25, 2024	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; Has not been previously published as pathogenic or benign to our knowledge; In silico analysis suggests this variant may impact gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown. -
Uncertain significance, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Feb 08, 2018	The SDHB c.529C>T; p.Arg177Cys variant (rs149091125), to our knowledge, is not reported in the medical literature, but it is classified as a variant of uncertain significance in ClinVar (Variant ID: 412469). This variant is also found in the non-Finnish European population with an allele frequency of 0.0036% (4/111,654 alleles) in the Genome Aggregation Database. The arginine at codon 177 is highly conserved considering 14 species up to bakerâ€™s yeast (Alamut software v2.10.0), and computational analyses predict that this variant affects the structure/function of the SDHB protein (SIFT: damaging, PolyPhen2: probably damaging). Based on the available information, the clinical significance of the p.Arg177Cys variant is uncertain at this time. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 03, 2023

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. RNA analysis performed to evaluate the impact of this missense change on mRNA splicing indicates it does not significantly alter splicing (Invitae). 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. ClinVar contains an entry for this variant (Variation ID: 412469). This variant has not been reported in the literature in individuals affected with SDHB-related conditions. This variant is present in population databases (rs149091125, gnomAD 0.004%). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 177 of the SDHB protein (p.Arg177Cys). -

Gastrointestinal stromal tumor

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Dec 26, 2023

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 04, 2023

The p.R177C variant (also known as c.529C>T), located in coding exon 5 of the SDHB gene, results from a C to T substitution at nucleotide position 529. The arginine at codon 177 is replaced by cysteine, an amino acid with highly dissimilar properties. Alterations at the same codon, p.R177G and p.R177H, have been reported in individuals diagnosed with paraganglioma or pheochromocytoma (von Dobschuetz E et al. Endocr. Relat. Cancer, 2015 Apr;22:191-204; Fishbein L et al. Ann. Surg. Oncol., 2013 May;20:1444-50; Michaowska I et al. Neuroendocrinology, 2015 Mar;101:321-30). However, functional studies of the p.R177H 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, p.R177C is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Hereditary pheochromocytoma-paraganglioma

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Oct 02, 2023

This missense variant replaces arginine with cysteine 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). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with SDHB-related disorders in the literature. This variant has been identified in 5/251376 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

0.97

BayesDel_addAF

Pathogenic

0.48

BayesDel_noAF

Pathogenic

0.55

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.76

D;.;D

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.81

FATHMM_MKL

Uncertain

0.94

LIST_S2

Pathogenic

0.99

D;D;D

M_CAP

Pathogenic

0.51

MetaRNN

Pathogenic

0.93

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.0

H;.;.

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.73

PROVEAN

Pathogenic

-7.2

D;.;.

REVEL

Pathogenic

0.80

Sift

Pathogenic

0.0

D;.;.

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;.;.

Vest4

0.92

MVP

1.0

MPC

0.81

ClinPred

1.0

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.96

gMVP

0.90

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.29

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.29

Position offset: 0

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