rs1553999798

Variant names:

• chr5-236603-A-G
• rs1553999798
• NM_004168.4:c.1432+4A>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_004168.4(SDHA):​c.1432+4A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,456 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SDHA NM_004168.4 splice_region, intron
• Scores: Splicing: ADA: 0.03460
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.00500
• Publications: 0 publications found

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

ENSG00000286001 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.91).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SDHA	NM_004168.4	c.1432+4A>G		splice_region_variant, intron_variant	Intron 10 of 14	ENST00000264932.11	NP_004159.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SDHA	ENST00000264932.11	c.1432+4A>G		splice_region_variant, intron_variant	Intron 10 of 14	1	NM_004168.4	ENSP00000264932.6
ENSG00000286001	ENST00000651543.1	n.*165+4A>G		splice_region_variant, intron_variant	Intron 9 of 23			ENSP00000499215.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461456 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727060

African (AFR) AF: 0.00 AC: 0 AN: 33460

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111648

Other (OTH) AF: 0.00 AC: 0 AN: 60376

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Pheochromocytoma/paraganglioma syndrome 5;C5700310:Mitochondrial complex II deficiency, nuclear type 1 Uncertain:1

Dec 17, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with SDHA-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change falls in intron 10 of the SDHA gene. It does not directly change the encoded amino acid sequence of the SDHA protein, but it affects a nucleotide within the consensus splice site of the intron. -

Hereditary cancer-predisposing syndrome Uncertain:1

Aug 24, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1432+4A>G intronic variant results from an A to G substitution 4 nucleotides after coding exon 10 in the SDHA gene. This nucleotide position is not well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will not have any significant effect on splicing. 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
BayesDel_noAF	Benign	-0.91
CADD	Benign	2.7
DANN	Benign	0.38
PhyloP100		0.0050
PromoterAI		-0.030	Neutral
Mutation Taster		=98/2	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.035
dbscSNV1_RF	Benign	0.32
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: rs1553999798; hg19: chr5-236718;