rs1060503764

Variant names:

• chr1-17022655-G-GA
• rs1060503764
• NM_003000.3:c.717dupT

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_003000.3(SDHB):​c.717dupT​(p.Leu240SerfsTer16) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. S239S) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SDHB NM_003000.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: -2.09
• Publications: 1 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: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 35 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-17022655-G-GA is Pathogenic according to our data. Variant chr1-17022655-G-GA is described in ClinVar as Pathogenic. ClinVar VariationId is 412481.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.717dupT	p.Leu240SerfsTer16	frameshift_variant	Exon 7 of 8	ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1	c.663dupT	p.Leu222SerfsTer16	frameshift_variant	Exon 7 of 8		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8	c.717dupT	p.Leu240SerfsTer16	frameshift_variant	Exon 7 of 8	1	NM_003000.3	ENSP00000364649.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Apr 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Leu240Serfs*16) in the SDHB gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 41 amino acid(s) of the SDHB protein. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SDHB-related conditions. ClinVar contains an entry for this variant (Variation ID: 412481). This variant disrupts a region of the SDHB protein in which other variant(s) (deletion of exon 8) have been determined to be pathogenic (Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Nov 10, 2015

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.717dupT pathogenic mutation, located in coding exon 7 of the SDHB gene, results from a duplication of T at nucleotide position 717, causing a translational frameshift with a predicted alternate stop codon. Similar alterations have been reported in this region in individuals with PCCs and PGLs (Amar L, J et al. Clin. Oncol. 2005 Dec; 23(34):8812-8; Neumann HP et al. Cancer Res. 2009 Apr; 69(8):3650-6; Lima J et al. J. Clin. Endocrinol. Metab. 2007 Dec; 92(12):4853-64). In addition to the evidence presented in the literature, since frameshifts are typically deleterious in nature, this alteration is interpreted as a disease-causing mutation (ACMG Recommendations for Standards for Interpretation and Reporting of Sequence Variations. Revision 2007. Genet Med. 2008;10:294). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-2.1
Mutation Taster		=33/167	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs1060503764; hg19: chr1-17349150;