rs367721665

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_004168.4(SDHA):​c.830C>A​(p.Thr277Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,164 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. T277M) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Consequence

SDHA
NM_004168.4 missense

Scores

2
8
9

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 3.00

Publications

6 publications found
Variant links:
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]
SDHA Gene-Disease associations (from GenCC):
  • hereditary pheochromocytoma-paraganglioma
    Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
  • pheochromocytoma/paraganglioma syndrome 5
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Illumina, Ambry Genetics, Labcorp Genetics (formerly Invitae)
  • mitochondrial complex II deficiency, nuclear type 1
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
  • neurodegeneration with ataxia and late-onset optic atrophy
    Inheritance: AD Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
  • Leigh syndrome
    Inheritance: AR Classification: MODERATE Submitted by: Ambry Genetics, ClinGen
  • familial isolated dilated cardiomyopathy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • gastrointestinal stromal tumor
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • Leigh syndrome with leukodystrophy
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • mitochondrial complex II deficiency
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • dilated cardiomyopathy 1GG
    Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SDHANM_004168.4 linkc.830C>A p.Thr277Lys missense_variant Exon 7 of 15 ENST00000264932.11 NP_004159.2 P31040-1A0A024QZ30

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
SDHAENST00000264932.11 linkc.830C>A p.Thr277Lys missense_variant Exon 7 of 15 1 NM_004168.4 ENSP00000264932.6 P31040-1
ENSG00000286001ENST00000651543.1 linkn.830C>A non_coding_transcript_exon_variant Exon 7 of 24 ENSP00000499215.1 A0A494C1T6

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152164
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000796
AC:
2
AN:
251232
AF XY:
0.00000736
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000176
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
Cov.:
57
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152164
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74344
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41442
American (AMR)
AF:
0.00
AC:
0
AN:
15278
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5198
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4830
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10624
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
67998
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000756
ExAC
AF:
0.0000165
AC:
2

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Dilated cardiomyopathy 1GG Uncertain:1
Sep 06, 2023
Baylor Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Pheochromocytoma/paraganglioma syndrome 5;C5700310:Mitochondrial complex II deficiency, nuclear type 1 Uncertain:1
Feb 02, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with lysine, which is basic and polar, at codon 277 of the SDHA protein (p.Thr277Lys). This variant is present in population databases (rs367721665, gnomAD 0.002%). 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: 539686). 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. -

Hereditary cancer-predisposing syndrome Uncertain:1
Jun 13, 2025
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.T277K variant (also known as c.830C>A), located in coding exon 7 of the SDHA gene, results from a C to A substitution at nucleotide position 830. The threonine at codon 277 is replaced by lysine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.86
BayesDel_addAF
Uncertain
0.073
D
BayesDel_noAF
Benign
-0.12
CADD
Benign
22
DANN
Uncertain
0.98
DEOGEN2
Benign
0.39
T;T;.;.
Eigen
Benign
0.18
Eigen_PC
Benign
0.10
FATHMM_MKL
Benign
0.75
D
LIST_S2
Pathogenic
0.98
D;D;D;D
M_CAP
Uncertain
0.11
D
MetaRNN
Uncertain
0.71
D;D;D;D
MetaSVM
Uncertain
-0.23
T
MutationAssessor
Uncertain
2.5
.;M;.;.
PhyloP100
3.0
PrimateAI
Uncertain
0.68
T
PROVEAN
Benign
-1.9
.;N;N;N
REVEL
Uncertain
0.33
Sift
Benign
0.14
.;T;T;T
Sift4G
Benign
0.29
T;T;T;T
Polyphen
0.98, 1.0
.;D;D;.
Vest4
0.72
MutPred
0.43
.;Gain of ubiquitination at T277 (P = 0.0162);Gain of ubiquitination at T277 (P = 0.0162);.;
MVP
0.75
MPC
1.4
ClinPred
0.69
D
GERP RS
4.1
Varity_R
0.85
gMVP
0.88
Mutation Taster
=63/37
polymorphism

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

Other links and lift over

dbSNP: rs367721665; hg19: chr5-231050; API