rs141230910
Variant summary
Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate
The NM_003000.3(SDHB):c.65G>T(p.Cys22Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,612,466 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts 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. C22S) has been classified as Likely benign.
Frequency
Consequence
NM_003000.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 0 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
SDHB | ENST00000375499.8 | c.65G>T | p.Cys22Phe | missense_variant | Exon 1 of 8 | 1 | NM_003000.3 | ENSP00000364649.3 | ||
SDHB | ENST00000466613.2 | n.77G>T | non_coding_transcript_exon_variant | Exon 1 of 3 | 2 | |||||
SDHB | ENST00000485515.5 | n.53G>T | non_coding_transcript_exon_variant | Exon 1 of 7 | 5 | ENSP00000519322.1 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152268Hom.: 0 Cov.: 31
GnomAD3 exomes AF: 0.00000824 AC: 2AN: 242626Hom.: 0 AF XY: 0.0000151 AC XY: 2AN XY: 132046
GnomAD4 exome AF: 0.0000144 AC: 21AN: 1460198Hom.: 0 Cov.: 30 AF XY: 0.0000207 AC XY: 15AN XY: 726344
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152268Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0AN XY: 74392
ClinVar
Submissions by phenotype
not provided Uncertain:2
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Identified in individuals with pheochromocytomas and/or paragangliomas (Garrett et al., 2022); This variant is associated with the following publications: (PMID: 34906457) -
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Hereditary pheochromocytoma-paraganglioma Uncertain:2
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
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Gastrointestinal stromal tumor;C1847319:Carney-Stratakis syndrome;C1861848:Paragangliomas 4;C5543176:Mitochondrial complex 2 deficiency, nuclear type 4 Uncertain:1
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Pheochromocytoma;C0238198:Gastrointestinal stromal tumor;C1861848:Paragangliomas 4 Uncertain:1
This sequence change replaces cysteine, which is neutral and slightly polar, with phenylalanine, which is neutral and non-polar, at codon 22 of the SDHB protein (p.Cys22Phe). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with SDHB-related conditions (PMID: 34906457). ClinVar contains an entry for this variant (Variation ID: 459163). 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 not expected to disrupt SDHB protein function with a negative predictive value of 95%. 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
The p.C22F variant (also known as c.65G>T), located in coding exon 1 of the SDHB gene, results from a G to T substitution at nucleotide position 65. The cysteine at codon 22 is replaced by phenylalanine, an amino acid with highly dissimilar properties. This variant was reported in individual(s) with features consistent with SDHB-related paraganglioma-pheochromocytoma syndrome (Ben Aim L et al. J Med Genet, 2022 Aug;59:785-792). However, this variant has also been detected in multiple individuals with no reported features of SDHB-related paraganglioma-pheochromocytoma syndrome (Ambry internal data). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -
Carney-Stratakis syndrome Uncertain:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at