rs980397872

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1PM2BP4

The NM_004168.4(SDHA):​c.1666A>G​(p.Met556Val) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000031 in 1,612,954 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. 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. M556T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SDHA
NM_004168.4 missense, splice_region

Scores

1
7
11

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 4.98

Publications

1 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 3 ACMG points.

PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 34 uncertain in NM_004168.4
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.31207356).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SDHANM_004168.4 linkc.1666A>G p.Met556Val missense_variant, splice_region_variant Exon 13 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.1666A>G p.Met556Val missense_variant, splice_region_variant Exon 13 of 15 1 NM_004168.4 ENSP00000264932.6 P31040-1
ENSG00000286001ENST00000651543.1 linkn.*399A>G splice_region_variant, non_coding_transcript_exon_variant Exon 12 of 24 ENSP00000499215.1 A0A494C1T6
ENSG00000286001ENST00000651543.1 linkn.*399A>G 3_prime_UTR_variant Exon 12 of 24 ENSP00000499215.1 A0A494C1T6

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152128
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000724
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:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000405
AC:
1
AN:
246656
AF XY:
0.00000746
show subpopulations
Gnomad AFR exome
AF:
0.0000682
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1460826
Hom.:
0
Cov.:
32
AF XY:
0.00000138
AC XY:
1
AN XY:
726686
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33424
American (AMR)
AF:
0.00
AC:
0
AN:
44582
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26116
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39690
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86196
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53336
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5538
European-Non Finnish (NFE)
AF:
9.00e-7
AC:
1
AN:
1111634
Other (OTH)
AF:
0.00
AC:
0
AN:
60310
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.500
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000197
AC:
3
AN:
152128
Hom.:
0
Cov.:
32
AF XY:
0.0000404
AC XY:
3
AN XY:
74306
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000724
AC:
3
AN:
41408
American (AMR)
AF:
0.00
AC:
0
AN:
15280
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5196
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10612
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68016
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.001311), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.392
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:
0.0000113

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Pheochromocytoma/paraganglioma syndrome 5;C5700310:Mitochondrial complex II deficiency, nuclear type 1 Uncertain:1
Jan 10, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 556 of the SDHA protein (p.Met556Val). This variant is present in population databases (no rsID available, gnomAD 0.01%). 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: 472349). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Benign". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect 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. -

Hereditary cancer-predisposing syndrome Uncertain:1
Oct 02, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.M556V variant (also known as c.1666A>G), located in coding exon 13 of the SDHA gene, results from an A to G substitution at nucleotide position 1666. The methionine at codon 556 is replaced by valine, an amino acid with highly 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. 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
Benign
0.075
BayesDel_addAF
Pathogenic
0.18
D
BayesDel_noAF
Uncertain
0.030
CADD
Benign
19
DANN
Benign
0.95
DEOGEN2
Benign
0.35
T;D;.;T
Eigen
Benign
-0.24
Eigen_PC
Benign
-0.17
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Uncertain
0.89
D;D;D;D
M_CAP
Uncertain
0.090
D
MetaRNN
Benign
0.31
T;T;T;T
MetaSVM
Benign
-0.45
T
MutationAssessor
Benign
1.7
.;L;.;.
PhyloP100
5.0
PrimateAI
Uncertain
0.57
T
PROVEAN
Benign
-2.2
.;N;N;N
REVEL
Uncertain
0.47
Sift
Uncertain
0.012
.;D;D;D
Sift4G
Benign
0.084
T;T;T;D
Polyphen
0.0020
.;B;.;.
Vest4
0.36
MutPred
0.36
.;Loss of sheet (P = 0.1158);.;.;
MVP
0.72
MPC
0.49
ClinPred
0.55
D
GERP RS
2.5
PromoterAI
-0.021
Neutral
Varity_R
0.61
gMVP
0.44
Mutation Taster
=86/14
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: rs980397872; hg19: chr5-251455; API