rs1553998191

Positions:

• chr5-228227-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_004168.4(SDHA):​c.664T>G​(p.Leu222Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: SDHA NM_004168.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.02

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SDHA	NM_004168.4	c.664T>G	p.Leu222Val	missense_variant	6/15	ENST00000264932.11	NP_004159.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SDHA	ENST00000264932.11	c.664T>G	p.Leu222Val	missense_variant	6/15	1	NM_004168.4	ENSP00000264932	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 28, 2023

This sequence change replaces leucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 222 of the SDHA protein (p.Leu222Val). This variant is not present in population databases (gnomAD no frequency). 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: 472398). 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. 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

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 29, 2022

The p.L222V variant (also known as c.664T>G), located in coding exon 6 of the SDHA gene, results from a T to G substitution at nucleotide position 664. The leucine at codon 222 is replaced by valine, 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	Benign	0.25
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Benign	0.32	T;.;.
Eigen	Benign	0.16
Eigen_PC	Benign	0.097
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Benign	0.061	D
MetaRNN	Uncertain	0.69	D;D;D
MetaSVM	Benign	-0.53	T
MutationAssessor	Benign	1.3	L;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-2.3	N;N;N
REVEL	Uncertain	0.37
Sift	Uncertain	0.0060	D;D;D
Sift4G	Uncertain	0.057	T;T;T
Polyphen		0.88	P;P;.
Vest4		0.79
MutPred		0.63		Gain of catalytic residue at L222 (P = 0.0157);Gain of catalytic residue at L222 (P = 0.0157);.;
MVP		0.65
MPC		0.80
ClinPred		0.82	D
GERP RS		0.24
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.68
gMVP		0.69

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: rs1553998191; hg19: chr5-228342; COSMIC: COSV53772149; COSMIC: COSV53772149;