1-17027864-T-C

Variant names:

• chr1-17027864-T-C
• rs759709073
• NM_003000.3:c.425A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_003000.3(SDHB):​c.425A>G​(p.Asp142Gly) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000142 in 1,404,350 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 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. D142V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SDHB NM_003000.3 missense, splice_region
• Scores: Splicing: ADA: 0.9230
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.48
• 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: Ambry Genetics, Genomics England PanelApp, 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: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 29 uncertain in NM_003000.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.948

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003000.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SDHB	NM_003000.3	MANE Select	c.425A>G	p.Asp142Gly	missense splice_region	Exon 5 of 8	NP_002991.2	P21912
	SDHB	NM_001407361.1		c.371A>G	p.Asp124Gly	missense splice_region	Exon 5 of 8	NP_001394290.1	A0AAQ5BHD9

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SDHB	ENST00000375499.8	TSL:1 MANE Select	c.425A>G	p.Asp142Gly	missense splice_region	Exon 5 of 8	ENSP00000364649.3	P21912
	SDHB	ENST00000714034.1		c.470A>G	p.Asp157Gly	missense splice_region	Exon 6 of 9	ENSP00000519325.1	A0AAQ5BHC9
	SDHB	ENST00000925621.1		c.419A>G	p.Asp140Gly	missense splice_region	Exon 5 of 8	ENSP00000595680.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000142 AC: 2 AN: 1404350 Hom.: 0 Cov.: 24 AF XY: 0.00000142 AC XY: 1 AN XY: 702158

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 32308

American (AMR) AF: 0.00 AC: 0 AN: 44652

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25766

East Asian (EAS) AF: 0.00 AC: 0 AN: 39418

South Asian (SAS) AF: 0.00 AC: 0 AN: 85122

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53078

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5662

European-Non Finnish (NFE) AF: 0.00000189 AC: 2 AN: 1059810

Other (OTH) AF: 0.00 AC: 0 AN: 58534

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000812204), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Hereditary cancer-predisposing syndrome (1)
-	1	-	Hereditary pheochromocytoma-paraganglioma (1)
-	1	-	Pheochromocytoma;C0238198:Gastrointestinal stromal tumor;C1861848:Pheochromocytoma/paraganglioma syndrome 4 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.76	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.4	H
PhyloP100		7.5
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-6.3	D
REVEL	Pathogenic	0.99
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0070	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.76		Loss of stability (P = 0.1223)
MVP		0.97
MPC		0.80
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.95
gMVP		0.96
Mutation Taster		=12/88	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.92
dbscSNV1_RF	Pathogenic	0.79
SpliceAI score (max)		0.060		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: rs759709073; hg19: chr1-17354359;