rs786201083

chr1-17044824-C-Achr1-17044824-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_003000.3(SDHB):c.137G>T(p.Arg46Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,790 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. R46G) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SDHB NM_003000.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.14

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 15 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 chr1-17044825-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 12785.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983
• PP5: Variant 1-17044824-C-A is Pathogenic according to our data. Variant chr1-17044824-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 412478.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SDHB	NM_003000.3	c.137G>T	p.Arg46Leu	missense_variant	2/8	ENST00000375499.8
SDHB	NM_001407361.1	c.137G>T	p.Arg46Leu	missense_variant	2/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SDHB	ENST00000375499.8	c.137G>T	p.Arg46Leu	missense_variant	2/8	1	NM_003000.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461790 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727202

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Pheochromocytoma;C0238198:Gastrointestinal stromal tumor;C1861848:Paragangliomas 4 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Nov 28, 2022

ClinVar contains an entry for this variant (Variation ID: 412478). For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg46 amino acid residue in SDHB. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 14500403, 15328326, 25972245). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects SDHB function (PMID: 23175444). 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. This missense change has been observed in individuals with pheochromocytoma and paraganglioma (PHEO-PGL) syndrome (Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 46 of the SDHB protein (p.Arg46Leu). -

Paragangliomas 4 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Oct 24, 2023

This variant is considered likely pathogenic. This variant has been reported in multiple individuals with clinical features of gene-specific disease [PMID: 34906457, 37529773, 31492822, 28374168]. This variant is expected to disrupt protein structure [Myriad internal data]. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 02, 2023

The p.R46L variant (also known as c.137G>T), located in coding exon 2 of the SDHB gene, results from a G to T substitution at nucleotide position 137. The arginine at codon 46 is replaced by leucine, an amino acid with dissimilar properties. This alteration has been observed in at least one individual with a personal and/or family history that is consistent with SDHB-related disease (Ambry internal data). This alteration has been reported in a paraganglioma-pheochromocytoma cohort, and authors characterized this alteration as having severely impaired function based on reduced oxidative growth, SDH activity and respiration, as well as increased mtDNA mutability following oxidative stress (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, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
Cadd	Pathogenic	33
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.94	D;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;D
M_CAP	Pathogenic	0.70	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	4.6	H;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.63	T
PROVEAN	Pathogenic	-5.5	D;.
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.94
MutPred		0.90		Loss of MoRF binding (P = 0.0368);.;
MVP		1.0
MPC		0.78
ClinPred		1.0	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.96
gMVP		0.95

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

Other links and lift over

dbSNP: rs772551056; hg19: chr1-17371319; COSMIC: COSV64965552;