rs773580529

Variant names:

• chr11-61445961-A-T
• rs773580529
• NM_017841.4:c.391A>T

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_Moderate BS1_Supporting BS2

The NM_017841.4(SDHAF2):​c.391A>T​(p.Ile131Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000547 in 1,461,868 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. 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. I131V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: SDHAF2 NM_017841.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 2.30
• Publications: 0 publications found

Genes affected

SDHAF2 (HGNC:26034): (succinate dehydrogenase complex assembly factor 2) This gene encodes a mitochondrial assembly factor needed for the flavination of a succinate dehydrogenase complex subunit (SDHA), which is required for activity of the succinate dehydrogenase complex. Mutations in this gene are associated with paraganglioma. [provided by RefSeq, May 2022]

SDHAF2 Gene-Disease associations (from GenCC):

• hereditary pheochromocytoma-paraganglioma

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• pheochromocytoma/paraganglioma syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P

ENSG00000256591 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -7 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.069149315).
• BS1: Variant frequency is greater than expected in population amr. GnomAdExome4 allele frequency = 0.00000547 (8/1461868) while in subpopulation AMR AF = 0.000157 (7/44724). AF 95% confidence interval is 0.0000728. There are 0 homozygotes in GnomAdExome4. There are 5 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAdExome4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHAF2	NM_017841.4	c.391A>T	p.Ile131Leu	missense_variant	Exon 4 of 4	ENST00000301761.7	NP_060311.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHAF2	ENST00000301761.7	c.391A>T	p.Ile131Leu	missense_variant	Exon 4 of 4	1	NM_017841.4	ENSP00000301761.3
ENSG00000256591	ENST00000541135.5	c.377+7841A>T		intron_variant	Intron 3 of 4	4		ENSP00000443130.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000318 AC: 8 AN: 251432 AF XY: 0.0000368

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000202

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: 0.000163

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461868 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 727234

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.000157 AC: 7 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53394

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112012

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000434 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary pheochromocytoma-paraganglioma Uncertain:2

Nov 20, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 131 of the SDHAF2 protein (p.Ile131Leu). This variant is present in population databases (rs773580529, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with SDHAF2-related conditions. ClinVar contains an entry for this variant (Variation ID: 532517). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. 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. -

Jun 26, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces isoleucine with leucine at codon 131 of the SDHAF2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with SDHAF2-related disorders in the literature. This variant has been identified in 8/251432 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Pheochromocytoma/paraganglioma syndrome 2 Uncertain:1

Aug 13, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Oct 06, 2023

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Jun 10, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.391A>T (p.I131L) alteration is located in exon 4 (coding exon 4) of the SDHAF2 gene. This alteration results from a A to T substitution at nucleotide position 391, causing the isoleucine (I) at amino acid position 131 to be replaced by a leucine (L). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.28	T
BayesDel_noAF	Benign	-0.36
CADD	Benign	15
DANN	Benign	0.95
DEOGEN2	Benign	0.21	T
Eigen	Benign	-0.54
Eigen_PC	Benign	-0.38
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.85	D
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.069	T
MetaSVM	Benign	-0.98	T
MutationAssessor	Benign	1.0	L
PhyloP100		2.3
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-0.51	N
REVEL	Benign	0.18
Sift	Benign	0.42	T
Sift4G	Benign	0.20	T
Polyphen		0.33	B
Vest4		0.16
MutPred		0.16		Gain of ubiquitination at K126 (P = 0.0964);
MVP		0.58
MPC		0.19
ClinPred		0.061	T
GERP RS		1.8
Varity_R		0.15
gMVP		0.38
Mutation Taster		=90/10	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

Other links and lift over

dbSNP: rs773580529; hg19: chr11-61213433;