rs148566767

Positions:

• chr1-161328416-C-A
• chr1-161328416-C-T

Variant summary

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

The NM_003001.5(SDHC):​c.98C>A​(p.Thr33Lys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. T33A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SDHC NM_003001.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.52

Genes affected

SDHC (HGNC:10682): (succinate dehydrogenase complex subunit C) This gene encodes one of four nuclear-encoded subunits that comprise succinate dehydrogenase, also known as mitochondrial complex II, a key enzyme complex of the tricarboxylic acid cycle and aerobic respiratory chains of mitochondria. The encoded protein is one of two integral membrane proteins that anchor other subunits of the complex, which form the catalytic core, to the inner mitochondrial membrane. There are several related pseudogenes for this gene on different chromosomes. Mutations in this gene have been associated with paragangliomas. Alternatively spliced transcript variants have been described. [provided by RefSeq, May 2013]

SDHC (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a topological_domain Mitochondrial matrix (size 32) in uniprot entity C560_HUMAN there are 8 pathogenic changes around while only 1 benign (89%) in NM_003001.5
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SDHC	NM_003001.5	c.98C>A	p.Thr33Lys	missense_variant	3/6	ENST00000367975.7	NP_002992.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SDHC	ENST00000367975.7	c.98C>A	p.Thr33Lys	missense_variant	3/6	1	NM_003001.5	ENSP00000356953.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Gastrointestinal stromal tumor;C1854336:Paragangliomas 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 17, 2019

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 sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with SDHC-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces threonine with lysine at codon 33 of the SDHC protein (p.Thr33Lys). The threonine residue is highly conserved and there is a moderate physicochemical difference between threonine and lysine. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Dec 19, 2023

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.36	T;.
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.89	D;D
M_CAP	Pathogenic	0.51	D
MetaRNN	Uncertain	0.43	T;T
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.3	M;M
PrimateAI	Uncertain	0.55	T
PROVEAN	Uncertain	-2.5	D;D
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0060	D;D
Sift4G	Uncertain	0.0050	D;D
Polyphen		0.89	P;D
Vest4		0.41
MutPred		0.41		Gain of ubiquitination at T33 (P = 0.0109);Gain of ubiquitination at T33 (P = 0.0109);
MVP		0.98
MPC		0.79
ClinPred		0.97	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.40
gMVP		0.94

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs148566767; hg19: chr1-161298206; COSMIC: COSV104418181;