1-17018923-C-G

Position:

• chr1-17018923-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_003000.3(SDHB):​c.801G>C​(p.Lys267Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. K267E) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SDHB NM_003000.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.48

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a chain Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial (size 251) in uniprot entity SDHB_HUMAN there are 195 pathogenic changes around while only 17 benign (92%) in NM_003000.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.908

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SDHB	NM_003000.3	c.801G>C	p.Lys267Asn	missense_variant	8/8	ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1	c.747G>C	p.Lys249Asn	missense_variant	8/8		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8	c.801G>C	p.Lys267Asn	missense_variant	8/8	1	NM_003000.3	ENSP00000364649.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251312 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135844

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.0000992

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 04, 2022

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. 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: 570629). This variant has not been reported in the literature in individuals affected with SDHB-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.01%). This sequence change replaces lysine, which is basic and polar, with asparagine, which is neutral and polar, at codon 267 of the SDHB protein (p.Lys267Asn). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.30
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.66	D
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.46	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-4.0	D
REVEL	Pathogenic	0.84
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.84
MutPred		0.69		Loss of methylation at K267 (P = 0.0316);
MVP		0.99
MPC		0.75
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.99
gMVP		0.92

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: rs771388711; hg19: chr1-17345418;