NM_003000.3:c.71A>G

Variant names:

• chr1-17053949-T-C
• rs878854580
• NM_003000.3:c.71A>G

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B.

Score: 1 - Uncertain Significance

1

PM2BP4

The NM_003000.3(SDHB):​c.71A>G​(p.Gln24Arg) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. 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. Q24H) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: SDHB NM_003000.3 missense, splice_region
• Scores: Splicing: ADA: 0.7681
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.27
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• Carney-Stratakis syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, G2P, Orphanet
• gastrointestinal stromal tumor

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
• hereditary pheochromocytoma-paraganglioma

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• pheochromocytoma

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• pheochromocytoma/paraganglioma syndrome 4

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• mitochondrial disease

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• renal cell carcinoma

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• mitochondrial complex 2 deficiency, nuclear type 4

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• Cowden disease

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• mitochondrial complex II deficiency

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.28949124).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHB	NM_003000.3	c.71A>G	p.Gln24Arg	missense_variant, splice_region_variant	Exon 1 of 8	ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1	c.71A>G	p.Gln24Arg	missense_variant, splice_region_variant	Exon 1 of 8		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8	c.71A>G	p.Gln24Arg	missense_variant, splice_region_variant	Exon 1 of 8	1	NM_003000.3	ENSP00000364649.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Pheochromocytoma;C0238198:Gastrointestinal stromal tumor;C1861848:Pheochromocytoma/paraganglioma syndrome 4 Uncertain:1

Feb 08, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ClinVar contains an entry for this variant (Variation ID: 1040802). 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). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. This variant has not been reported in the literature in individuals affected with SDHB-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 24 of the SDHB protein (p.Gln24Arg). -

Hereditary cancer-predisposing syndrome Uncertain:1

Sep 16, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Q24R variant (also known as c.71A>G), located in coding exon 1 of the SDHB gene, results from an A to G substitution at nucleotide position 71. The glutamine at codon 24 is replaced by arginine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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	0.087
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	21
DANN	Benign	0.94
DEOGEN2	Benign	0.36	T
Eigen	Benign	-0.44
Eigen_PC	Benign	-0.23
FATHMM_MKL	Benign	0.22	N
LIST_S2	Benign	0.60	T
M_CAP	Pathogenic	0.52	D
MetaRNN	Benign	0.29	T
MetaSVM	Uncertain	0.39	D
MutationAssessor	Benign	0.14	N
PhyloP100		1.3
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-0.72	N
REVEL	Uncertain	0.43
Sift	Benign	0.42	T
Sift4G	Benign	0.67	T
Polyphen		0.0	B
Vest4		0.23
MutPred		0.43		Gain of MoRF binding (P = 0.01);
MVP		0.89
MPC		0.18
ClinPred		0.28	T
GERP RS		4.0
PromoterAI		0.12	Neutral
RBP_binding_hub_radar		0.97
RBP_regulation_power_radar		2.7
Varity_R		0.15
gMVP		0.44
Mutation Taster		=80/20	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.77
dbscSNV1_RF	Benign	0.64
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs878854580; hg19: chr1-17380444;