1-17028628-T-G

Variant names:

• chr1-17028628-T-G
• rs74315372
• NM_003000.3:c.395A>C

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_003000.3(SDHB):​c.395A>C​(p.His132Pro) variant causes a missense change involving the alteration of a 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H132R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SDHB NM_003000.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.33

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 16 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 16 uncertain in NM_003000.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.982
• PP5: Variant 1-17028628-T-G is Pathogenic according to our data. Variant chr1-17028628-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 12787.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHB	NM_003000.3	c.395A>C	p.His132Pro	missense_variant	Exon 4 of 8	ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1	c.369+26A>C		intron_variant	Intron 4 of 7		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8	c.395A>C	p.His132Pro	missense_variant	Exon 4 of 8	1	NM_003000.3	ENSP00000364649.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

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

Oct 24, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ClinVar contains an entry for this variant (Variation ID: 12787). This sequence change replaces histidine with proline at codon 132 of the SDHB protein (p.His132Pro). The histidine residue is highly conserved and there is a moderate physicochemical difference between histidine and proline. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individuals with clinical features of SDHB-related conditions (PMID: 14715873, 31492822). It has also been observed to segregate with disease in related individuals. 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. For these reasons, this variant has been classified as Pathogenic. -

Paragangliomas 4 Pathogenic:1

Jan 01, 2004

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Nov 30, 2020

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.H132P variant (also known as c.395A>C), located in coding exon 4 of the SDHB gene, results from an A to C substitution at nucleotide position 395. The histidine at codon 132 is replaced by proline, an amino acid with similar properties. This alteration was reported in two siblings diagnosed with PGL at ages 25 and 53; both tumors exhibited LOH, and RT-PCR expression analysis confirmed that p.H132P was the only expressed allele in the tumors (Maier-Woelfle M et al. J. Clin. Endocrinol. Metab., 2004 Jan;89:362-7). 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	0.97
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.92	D;.;D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D;D;D
M_CAP	Pathogenic	0.49	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.3	H;.;.
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-9.4	D;.;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;.;.
Sift4G	Uncertain	0.0080	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.90
MutPred		0.88		Gain of catalytic residue at P131 (P = 0.0377);.;.;
MVP		0.99
MPC		0.87
ClinPred		1.0	D
GERP RS		6.2
Varity_R		0.97
gMVP		0.94

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: rs74315372; hg19: chr1-17355123;