rs878854573

chr1-17044806-G-Achr1-17044806-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_003000.3(SDHB):c.155C>T(p.Ala52Val) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,818 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts 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. A52D) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SDHB NM_003000.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.04

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 Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 16 uncertain in NM_003000.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.36481643).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SDHB	NM_003000.3	c.155C>T	p.Ala52Val	missense_variant	2/8	ENST00000375499.8
SDHB	NM_001407361.1	c.155C>T	p.Ala52Val	missense_variant	2/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SDHB	ENST00000375499.8	c.155C>T	p.Ala52Val	missense_variant	2/8	1	NM_003000.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251374 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135868

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461818 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727210

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 26, 2019

The p.A52V variant (also known as c.155C>T), located in coding exon 2 of the SDHB gene, results from a C to T substitution at nucleotide position 155. The alanine at codon 52 is replaced by valine, an amino acid with similar properties. This amino acid position is not well 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	0.089
BayesDel_addAF	Uncertain	0.016	T
BayesDel_noAF	Benign	-0.22
Cadd	Uncertain	23
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.66	D;.
Eigen	Benign	-0.083
Eigen_PC	Benign	0.11
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.92	D;D
M_CAP	Uncertain	0.094	D
MetaRNN	Benign	0.36	T;T
MetaSVM	Uncertain	0.53	D
MutationAssessor	Benign	1.7	L;.
MutationTaster	Benign	0.95	N
PrimateAI	Benign	0.29	T
PROVEAN	Benign	-1.2	N;.
REVEL	Uncertain	0.34
Sift	Benign	0.034	D;.
Sift4G	Benign	0.35	T;T
Polyphen		0.0	B;.
Vest4		0.11
MutPred		0.38		Gain of methylation at K51 (P = 0.0387);.;
MVP		0.91
MPC		0.17
ClinPred		0.59	D
GERP RS		4.7
Varity_R		0.059
gMVP		0.40

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs878854573; hg19: chr1-17371301; COSMIC: COSV64965572;