rs1057517540

Positions:

• chr5-233577-TGT-CAC

Variant summary

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

The NM_004168.4(SDHA):​c.996_998delinsCAC​(p.Val333Thr) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. PV332PI) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SDHA NM_004168.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 6.89

Genes affected

SDHA (HGNC:10680): (succinate dehydrogenase complex flavoprotein subunit A) This gene encodes a major catalytic subunit of succinate-ubiquinone oxidoreductase, a complex of the mitochondrial respiratory chain. The complex is composed of four nuclear-encoded subunits and is localized in the mitochondrial inner membrane. Mutations in this gene have been associated with a form of mitochondrial respiratory chain deficiency known as Leigh Syndrome. A pseudogene has been identified on chromosome 3q29. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jun 2014]

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	UniProt
SDHA	NM_004168.4	c.996_998delinsCAC	p.Val333Thr	missense_variant	8/15	ENST00000264932.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SDHA	ENST00000264932.11	c.996_998delinsCAC	p.Val333Thr	missense_variant	8/15	1	NM_004168.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Paragangliomas 5 Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Apr 21, 2023	This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
Uncertain significance, criteria provided, single submitter	clinical testing	St. Jude Molecular Pathology, St. Jude Children's Research Hospital	Dec 01, 2022	The SDHA c.996_998delinsCAC (p.Val333Thr) missense change is absent in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/). In silico tools predict a benign effect of this variant on protein function, but to our knowledge these predictions have not been confirmed by functional studies. To our knowledge, this variant has not been reported in individuals with SDHA-associated tumors. In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Dec 02, 2015	- -

Paragangliomas 5;C5700310:Mitochondrial complex II deficiency, nuclear type 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 06, 2023

This sequence change replaces valine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 333 of the SDHA protein (p.Val333Thr). Information on the frequency of this variant in the gnomAD database is not available, as this variant may be reported differently in the database. This variant has not been reported in the literature in individuals affected with SDHA-related conditions. ClinVar contains an entry for this variant (Variation ID: 371798). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 12, 2023

The c.996_998delTGTinsCAC variant (also known as p.V333T), located in coding exon 8 of the SDHA gene, results from an in-frame deletion of TGT and insertion of CAC at nucleotide positions 996 to 998. This results in the substitution of the valine residue for a threonine residue at codon 333, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be neutral by in silico analysis (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs1057517540; hg19: chr5-233692;