NM_003000.3:c.221A>C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1PM2PM5PP3_ModeratePP5_Very_Strong

The NM_003000.3(SDHB):c.221A>C(p.Asp74Ala) variant causes a missense change. The variant allele was found at a frequency of 0.00000248 in 1,613,338 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D74G) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SDHB
NM_003000.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 7.03

Publications

0 publications found

Variant links:

Genes affected

SDHB (HGNC:10681): (succinate dehydrogenase complex iron sulfur subunit B) This tumor suppressor gene encodes the iron-sulfur protein subunit of the succinate dehydrogenase (SDH) enzyme complex which plays a critical role in mitochondria. The SDH enzyme complex is composed of four nuclear-encoded subunits. This enzyme complex converts succinate to fumarate which releases electrons as part of the citric acid cycle, and the enzyme complex additionally provides an attachment site for released electrons to be transferred to the oxidative phosphorylation pathway. The SDH enzyme complex plays a role in oxygen-related gene regulation through its conversion of succinate, which is an oxygen sensor that stabilizes the hypoxia-inducible factor 1 (HIF1) transcription factor. Sporadic and familial mutations in this gene result in paragangliomas, pheochromocytoma, and gastrointestinal stromal tumors, supporting a link between mitochondrial dysfunction and tumorigenesis. Mutations in this gene are also implicated in nuclear type 4 mitochondrial complex II deficiency. [provided by RefSeq, Jun 2022]

SDHB Gene-Disease associations (from GenCC):

Carney-Stratakis syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, G2P, Orphanet
gastrointestinal stromal tumor
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
hereditary pheochromocytoma-paraganglioma
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
pheochromocytoma
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
pheochromocytoma/paraganglioma syndrome 4
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae)
mitochondrial disease
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
renal cell carcinoma
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
mitochondrial complex 2 deficiency, nuclear type 4
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
Cowden disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
mitochondrial complex II deficiency
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

SDHB links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 16 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 32 uncertain in NM_003000.3

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-17033125-T-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2005694.Status of the report is criteria_provided_single_submitter, 1 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.911

PP5

Variant 1-17033125-T-G is Pathogenic according to our data. Variant chr1-17033125-T-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 230694.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHB	NM_003000.3 link	c.221A>C	p.Asp74Ala	missense_variant	Exon 3 of 8	ENST00000375499.8	NP_002991.2	P21912
SDHB	NM_001407361.1 link	c.221A>C	p.Asp74Ala	missense_variant	Exon 3 of 8		NP_001394290.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHB	ENST00000375499.8 link	c.221A>C	p.Asp74Ala	missense_variant	Exon 3 of 8	1	NM_003000.3	ENSP00000364649.3		P21912

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152202

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.00000398

AC:

AN:

251336

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

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:

AN:

1461136

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726922

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33464

American (AMR)

AF:

0.0000447

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86232

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111344

Other (OTH)

AF:

0.00

AC:

AN:

60368

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152202

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74356

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41456

American (AMR)

AF:

0.000131

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:2

Oct 25, 2024

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Identified in individuals undergoing screening for Hereditary PGL/PCC syndrome in published literature (PMID: 32741965); 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; This variant is associated with the following publications: (PMID: 34906457, 32741965) -

Feb 11, 2022

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The SDHB c.221A>C; p.Asp74Ala variant (rs876658713) is reported in the literature in an individual affected with hereditary paraganglioma-pheochromocytoma syndrome (Greenberg 2020). This variant has also been observed in multiple patients affected with paraganglioma and renal cell carcinoma including SDH-deficient tumors at ARUP and other laboratories (external communications). This variant is also reported in ClinVar (Variation ID: 230694), but is only observed on one allele in the Genome Aggregation Database, indicating it is not a common polymorphism. The aspartate at codon 74 is highly conserved, and computational analyses predict that this variant is deleterious (REVEL: 0.939). Based on available information, this variant is considered to be likely pathogenic. References: Greenberg SE et al. Tumor detection rates in screening of individuals with SDHx-related hereditary paraganglioma-pheochromocytoma syndrome. Genet Med. 2020 Dec;22(12):2101-2107. PMID: 32741965. -

Hereditary pheochromocytoma-paraganglioma

Pathogenic:2

Apr 30, 2024

All of Us Research Program, National Institutes of Health

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces aspartic acid with alanine at codon 74 of the SDHB protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with paraganglioma (PGL), gastrointestinal stromal tumor (GIST), and renal cell carcinoma (RCC) (PMID: 34255389, ClinVar: SCV000274333, SCV001772221, SCV000605079). This variant has been identified in 1/251336 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -

Jun 04, 2024

Color Diagnostics, LLC DBA Color Health

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces aspartic acid with alanine at codon 74 of the SDHB protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with paraganglioma, gastrointestinal stromal tumor, and renal cell carcinoma (PMID: 34255389, ClinVar: SCV000274333, SCV001772221, SCV000605079). This variant has been identified in 1/251336 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -

Pheochromocytoma/paraganglioma syndrome 4

Pathogenic:1

Nov 16, 2023

Human Genome Sequencing Center Clinical Lab, Baylor College of Medicine

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.221A>C (p.Asp74Ala) variant in the SDHB gene is located on the exon 3 and is predicted to replace aspartic acid with alanine at codon 74 (p.Asp74Ala). The variant has been reported in individuals with paraganglioma/pheochromocytoma (PMID: 34255389, 34906457). The variant is reported to segregate with diseease by several ClinVar submitters (ID: 230694). The variant is rare in general population according to gnomAD (1/251336). Computational prediction algorithms suggest a deleterious impact for this variant (REVEL score 0.939). Therefore, the c.221A>C (p.Asp74Ala) variant of SDHB has been classified as likely pathogenic. -

Pheochromocytoma;C0238198:Gastrointestinal stromal tumor;C1861848:Pheochromocytoma/paraganglioma syndrome 4

Pathogenic:1

Nov 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with alanine, which is neutral and non-polar, at codon 74 of the SDHB protein (p.Asp74Ala). This variant is present in population databases (no rsID available, gnomAD 0.006%). This missense change has been observed in individuals with paraganglioma (PGL), gastrointestinal stromal tumor, and renal cell carcinoma including SDH-deficient tumors ( (external communications, internal data). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 230694). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt SDHB protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -

Gastrointestinal stromal tumor

Pathogenic:1

Feb 19, 2024

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Pathogenic:1

Jul 23, 2024

Ambry Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.221A>C (p.D74A) alteration is located in exon 3 (coding exon 3) of the SDHB gene. This alteration results from a A to C substitution at nucleotide position 221, causing the aspartic acid (D) at amino acid position 74 to be replaced by an alanine (A). Based on data from gnomAD, the C allele has an overall frequency of <0.001% (1/251336) total alleles studied. The highest observed frequency was 0.003% (1/34586) of Latino alleles. This alteration has been observed in multiple individuals with a personal and/or family history that is consistent with SDHB-related disease and co-segregated with disease in at least one family (Greenberg, 2021; Ambry internal data). This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.44

BayesDel_noAF

Pathogenic

0.48

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.92

D;.;D

Eigen

Pathogenic

0.92

Eigen_PC

Pathogenic

0.84

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.99

D;D;D

M_CAP

Pathogenic

0.58

MetaRNN

Pathogenic

0.91

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.8

H;.;.

PhyloP100

7.0

PrimateAI

Uncertain

0.74

PROVEAN

Pathogenic

-7.3

D;.;.

REVEL

Pathogenic

0.94

Sift

Pathogenic

0.0

D;.;.

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;.;.

Vest4

0.92

MutPred

0.63

Loss of methylation at K78 (P = 0.1718);.;.;

MVP

0.98

MPC

0.75

ClinPred

1.0

GERP RS

5.4

Varity_R

0.95

gMVP

0.90

Mutation Taster

=2/98

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over