rs786201063

Positions:

• chr1-17033059-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_003000.3(SDHB):​c.286+1G>A variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: SDHB NM_003000.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 6.92

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 Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-17033059-C-T is Pathogenic according to our data. Variant chr1-17033059-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 183757.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-17033059-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SDHB	NM_003000.3	c.286+1G>A		splice_donor_variant, intron_variant		ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1	c.286+1G>A		splice_donor_variant, intron_variant			NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8	c.286+1G>A		splice_donor_variant, intron_variant		1	NM_003000.3	ENSP00000364649.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Paragangliomas 4 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	MGZ Medical Genetics Center	Aug 25, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Feb 08, 2024	This variant is considered pathogenic. This variant occurs within a consensus splice junction and is predicted to result in abnormal mRNA splicing of either an out-of-frame exon or an in-frame exon necessary for protein stability and/or normal function. This variant has been reported in multiple individuals with clinical features of gene-specific disease [PMID: 30201732, 33391357, 17538171, 27539324]. -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 09, 2024	Canonical splice site variant in a gene for which loss-of-function is a known mechanism of disease; Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 19802898, 25525159, 17308434, 16912137, 27539324, 26960314, 28374168, 22517557, 25683602, 17200167, 28152038, 19454582, 29623478, 17102085, 31492822, 34439371) -
Pathogenic, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	May 13, 2021	The SDHB c.286+1G>A variant (rs786201063), also known as IVS3+1G>A, is reported in the literature in multiple individuals affected with paragangliomas and pheochromocytomas (Brouwers 2006, Isobe 2007, Pandit 2016, Timmers 2007). This variant is reported in ClinVar (Variation ID: 183757). This variant is absent from the Genome Aggregation Database, indicating it is not a common polymorphism. This variant disrupts the canonical splice donor site of intron three, which is likely to negatively impact gene function. Based on available information, this variant is considered to be pathogenic. References: Brouwers FM et al. High frequency of SDHB germline mutations in patients with malignant catecholamine-producing paragangliomas: implications for genetic testing. J Clin Endocrinol Metab. 2006 Nov;91(11):4505-9. PMID: 16912137. Isobe K et al. Novel germline mutations in the SDHB and SDHD genes in Japanese pheochromocytomas. Horm Res. 2007;68(2):68-71. PMID: 17308434. Pandit R et al. Germline mutations and genotype-phenotype correlation in Asian Indian patients with pheochromocytoma and paraganglioma. Eur J Endocrinol. 2016 Oct;175(4):311-23. PMID: 27539324. Timmers HJ et al. Clinical presentations, biochemical phenotypes, and genotype-phenotype correlations in patients with succinate dehydrogenase subunit B-associated pheochromocytomas and paragangliomas. J Clin Endocrinol Metab. 2007 Mar;92(3):779-86. PMID: 17200167. -

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 30, 2024

This sequence change affects a donor splice site in intron 3 of the SDHB gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in SDHB are known to be pathogenic (PMID: 19454582, 19802898). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with paraganglioma (PMID: 16912137, 17308434, 27539324). This variant is also known as IVS3+1 G>A. ClinVar contains an entry for this variant (Variation ID: 183757). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Gastrointestinal stromal tumor Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Jan 18, 2022

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 12, 2024

The c.286+1G>A intronic pathogenic mutation results from a G to A substitution one nucleotide after coding exon 3 of the SDHB gene. This pathogenic variant has been reported in multiple unrelated individuals diagnosed with paragangliomas/pheochromocytomas (Brouwers FM et al. J. Clin. Endocrinol. Metab. 2006 Nov;91:4505-9; Timmers HJ et al. J. Clin. Endocrinol. Metab. 2007 Mar;92:779-86; Isobe K et al. Horm. Res. 2007 Feb;68:68-71; Pandit R et al. Eur. J. Endocrinol. 2016 Oct;175:311-23). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Hereditary pheochromocytoma-paraganglioma Pathogenic:1

Pathogenic, no assertion criteria provided

research

Section on Medical Neuroendocrinolgy, National Institutes of Health

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.10
CADD	Pathogenic	31
DANN	Uncertain	0.98
Eigen	Pathogenic	0.81
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.94		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.94		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs786201063; hg19: chr1-17359554;