rs1060503720

chr5-225425-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_004168.4(SDHA):c.319A>G(p.Ile107Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,460,190 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. I107M) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: SDHA NM_004168.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.60

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 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 17 uncertain in NM_004168.4
• 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.319A>G	p.Ile107Val	missense_variant	4/15	ENST00000264932.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SDHA	ENST00000264932.11	c.319A>G	p.Ile107Val	missense_variant	4/15	1	NM_004168.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1460190 Hom.: 0 Cov.: 32 AF XY: 0.00000551 AC XY: 4 AN XY: 726396

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 07, 2022	The p.I107V variant (also known as c.319A>G), located in coding exon 4 of the SDHA gene, results from an A to G substitution at nucleotide position 319. The isoleucine at codon 107 is replaced by valine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Aug 06, 2021	- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 19, 2024

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 107 of the SDHA protein (p.Ile107Val). This variant is not present in population databases (gnomAD no frequency). 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: 412378). 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 not expected to disrupt SDHA protein function with a negative predictive value of 95%. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Uncertain	0.075	D
BayesDel_noAF	Benign	-0.13
Cadd	Benign	22
Dann	Benign	0.97
DEOGEN2	Benign	0.29	T;T;.
Eigen	Uncertain	0.32
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Benign	0.030	D
MetaRNN	Uncertain	0.65	D;D;D
MetaSVM	Benign	-0.43	T
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.76	T
Sift4G	Benign	0.17	T;T;T
Polyphen		0.35, 0.17	.;B;B
Vest4		0.63
MutPred		0.77		Gain of disorder (P = 0.1242);Gain of disorder (P = 0.1242);Gain of disorder (P = 0.1242);
MVP		0.74
MPC		0.57
ClinPred		0.56	D
GERP RS		5.3
Varity_R		0.30
gMVP		0.69

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

Publications

LitVar

Other links and lift over

dbSNP: rs1060503720; hg19: chr5-225540;