NM_004168.4:c.1775A>G

Variant names:

• chr5-251449-A-G
• rs1554001966
• NM_004168.4:c.1775A>G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_004168.4(SDHA):​c.1775A>G​(p.His592Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,646 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. H592H) has been classified as Benign.

• 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: 8.80

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]

ENSG00000286001 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHA	NM_004168.4	c.1775A>G	p.His592Arg	missense_variant	Exon 13 of 15	ENST00000264932.11	NP_004159.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHA	ENST00000264932.11	c.1775A>G	p.His592Arg	missense_variant	Exon 13 of 15	1	NM_004168.4	ENSP00000264932.6
ENSG00000286001	ENST00000651543.1	n.*508A>G		non_coding_transcript_exon_variant	Exon 12 of 24			ENSP00000499215.1
ENSG00000286001	ENST00000651543.1	n.*508A>G		3_prime_UTR_variant	Exon 12 of 24			ENSP00000499215.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461646 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727130

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

Alfa AF: 0.0000468 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Oct 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces histidine, which is basic and polar, with arginine, which is basic and polar, at codon 592 of the SDHA protein (p.His592Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with paraganglioma-pheochromocytoma syndromes (PMID: 30877234). ClinVar contains an entry for this variant (Variation ID: 472357). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SDHA protein function. 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. -

Dilated cardiomyopathy 1GG Uncertain:1

Dec 18, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Sep 15, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.H592R variant (also known as c.1775A>G), located in coding exon 13 of the SDHA gene, results from an A to G substitution at nucleotide position 1775. The histidine at codon 592 is replaced by arginine, an amino acid with highly similar properties. This alteration was identified in an individual diagnosed with a paraganglioma and/or pheochromocytoma (Ben Aim L et al. J Med Genet, 2019 08;56:513-520). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.62	D;D;.;D
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D;D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	5.3	.;H;.;.
PrimateAI	Pathogenic	0.80	D
PROVEAN	Pathogenic	-6.9	.;D;D;D
REVEL	Pathogenic	0.88
Sift	Uncertain	0.0010	.;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D
Polyphen		1.0	.;D;.;.
Vest4		0.97
MutPred		0.90		.;Gain of MoRF binding (P = 0.0106);.;.;
MVP		0.94
MPC		1.4
ClinPred		1.0	D
GERP RS		3.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2
Varity_R		0.99
gMVP		0.98

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: rs1554001966; hg19: chr5-251564;