rs138979875

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_003000.3(SDHB):c.50C>T(p.Thr17Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,613,078 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign 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. T17A) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

SDHB
NM_003000.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 0.453

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_benign. Variant got -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.122154).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SDHB	NM_003000.3 linkuse as main transcript	c.50C>T	p.Thr17Ile	missense_variant	1/8	ENST00000375499.8
SDHB	NM_001407361.1 linkuse as main transcript	c.50C>T	p.Thr17Ile	missense_variant	1/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris
SDHB	ENST00000375499.8 linkuse as main transcript	c.50C>T	p.Thr17Ile	missense_variant	1/8	1	NM_003000.3	P1
SDHB	ENST00000466613.2 linkuse as main transcript	n.62C>T		non_coding_transcript_exon_variant	1/3	2
SDHB	ENST00000485515.5 linkuse as main transcript	n.38C>T		non_coding_transcript_exon_variant	1/7	5

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152264

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.000288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000206

AC:

AN:

243268

Hom.:

AF XY:

0.0000302

AC XY:

AN XY:

132444

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000301

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000184

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000144

AC:

AN:

1460814

Hom.:

Cov.:

AF XY:

0.0000165

AC XY:

AN XY:

726680

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.000498

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000540

Gnomad4 OTH exome

AF:

0.0000332

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152264

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74392

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.000288

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000450

Hom.:

Bravo

AF:

0.0000264

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 27, 2024

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 17 of the SDHB protein (p.Thr17Ile). This variant is present in population databases (rs138979875, gnomAD 0.03%). 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: 459151). 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 95%. 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

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Feb 03, 2022

In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Gastrointestinal stromal tumor

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Aug 31, 2023

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 26, 2022

The p.T17I variant (also known as c.50C>T), located in coding exon 1 of the SDHB gene, results from a C to T substitution at nucleotide position 50. The threonine at codon 17 is replaced by isoleucine, an amino acid with similar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

0.0061

BayesDel_noAF

Benign

-0.23

Cadd

Benign

8.5

Dann

Benign

0.80

DEOGEN2

Benign

0.36

Eigen

Benign

-1.0

Eigen_PC

Benign

-1.0

FATHMM_MKL

Benign

0.011

LIST_S2

Benign

0.62

M_CAP

Pathogenic

0.30

MetaRNN

Benign

0.12

MetaSVM

Uncertain

0.45

MutationAssessor

Benign

0.0

MutationTaster

Benign

1.0

PrimateAI

Benign

0.48

PROVEAN

Benign

-1.4

REVEL

Uncertain

0.34

Sift

Benign

0.33

Sift4G

Benign

0.17

Polyphen

0.0

Vest4

0.18

MVP

0.62

MPC

0.18

ClinPred

0.033

GERP RS

0.46

RBP_binding_hub_radar

0.97

RBP_regulation_power_radar

2.1

Varity_R

0.037

gMVP

0.37

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