1-17024077-G-T

Position:

• chr1-17024077-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The ENST00000375499.8(SDHB):​c.541-3C>A variant causes a splice region, splice polypyrimidine tract, intron 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. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SDHB ENST00000375499.8 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.9982
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.29

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SDHB	NM_003000.3	c.541-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000375499.8	NP_002991.2
SDHB	NM_001407361.1	c.487-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant			NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8	c.541-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_003000.3	ENSP00000364649	P1
SDHB	ENST00000463045.3	c.370-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		3		ENSP00000481376
SDHB	ENST00000491274.6	c.499-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		5		ENSP00000480482
SDHB	ENST00000485515.5	n.475-3C>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1455344 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 724338

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 31, 2022

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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. ClinVar contains an entry for this variant (Variation ID: 1422883). 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 falls in intron 5 of the SDHB gene. It does not directly change the encoded amino acid sequence of the SDHB protein. It affects a nucleotide within the consensus splice site. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.21
CADD	Benign	17
DANN	Benign	0.94

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.80
SpliceAI score (max)		0.14		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-17350572;