rs1554002478

Variant names:

• chr5-254461-C-G
• rs1554002478
• NM_004168.4:c.1863C>G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_004168.4(SDHA):​c.1863C>G​(p.His621Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 30)
• Consequence: SDHA NM_004168.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 0.952

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.749

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHA	NM_004168.4	c.1863C>G	p.His621Gln	missense_variant	Exon 14 of 15	ENST00000264932.11	NP_004159.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHA	ENST00000264932.11	c.1863C>G	p.His621Gln	missense_variant	Exon 14 of 15	1	NM_004168.4	ENSP00000264932.6
ENSG00000286001	ENST00000651543.1	n.*596C>G		non_coding_transcript_exon_variant	Exon 13 of 24			ENSP00000499215.1
ENSG00000286001	ENST00000651543.1	n.*596C>G		3_prime_UTR_variant	Exon 13 of 24			ENSP00000499215.1

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 30

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

May 23, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C15"). This variant has not been reported in the literature in individuals with SDHA-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces histidine with glutamine at codon 621 of the SDHA protein (p.His621Gln). The histidine residue is highly conserved and there is a small physicochemical difference between histidine and glutamine. -

Dilated cardiomyopathy 1GG Uncertain:1

Aug 18, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Jan 18, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.H621Q variant (also known as c.1863C>G), located in coding exon 14 of the SDHA gene, results from a C to G substitution at nucleotide position 1863. The histidine at codon 621 is replaced by glutamine, an amino acid with highly similar properties. This amino acid position is conserved. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.040
CADD	Benign	19
DANN	Benign	0.93
DEOGEN2	Benign	0.39	T;D;.;.
Eigen	Benign	-0.096
Eigen_PC	Benign	-0.12
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.97	D;D;D;D
M_CAP	Pathogenic	0.60	D
MetaRNN	Pathogenic	0.75	D;D;D;D
MetaSVM	Uncertain	-0.010	T
MutationAssessor	Uncertain	2.5	.;M;.;.
PrimateAI	Uncertain	0.62	T
PROVEAN	Uncertain	-4.1	.;D;D;D
REVEL	Uncertain	0.60
Sift	Uncertain	0.011	.;D;D;D
Sift4G	Uncertain	0.040	D;D;D;T
Polyphen		0.53, 0.97	.;P;D;.
Vest4		0.58
MutPred		0.48		.;Loss of sheet (P = 0.1158);.;.;
MVP		0.83
MPC		0.59
ClinPred		0.96	D
GERP RS		2.3
Varity_R		0.91
gMVP		0.73

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: rs1554002478; hg19: chr5-254576;