1-55063507-A-G
Variant summary
Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong
The NM_174936.4(PCSK9):c.2002A>G(p.Ser668Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000248 in 1,613,848 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 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. S668I) has been classified as Uncertain significance.
Frequency
Consequence
NM_174936.4 missense
Scores
Clinical Significance
Conservation
Publications
- hypercholesterolemia, autosomal dominant, 3Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
- homozygous familial hypercholesterolemiaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_benign. The variant received -4 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| PCSK9 | NM_174936.4 | c.2002A>G | p.Ser668Gly | missense_variant | Exon 12 of 12 | ENST00000302118.5 | NP_777596.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| PCSK9 | ENST00000302118.5 | c.2002A>G | p.Ser668Gly | missense_variant | Exon 12 of 12 | 1 | NM_174936.4 | ENSP00000303208.5 |
Frequencies
GnomAD3 genomes AF: 0.0000394 AC: 6AN: 152228Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000479 AC: 12AN: 250532 AF XY: 0.0000295 show subpopulations
GnomAD4 exome AF: 0.0000233 AC: 34AN: 1461620Hom.: 0 Cov.: 30 AF XY: 0.0000206 AC XY: 15AN XY: 727122 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000394 AC: 6AN: 152228Hom.: 0 Cov.: 33 AF XY: 0.0000538 AC XY: 4AN XY: 74368 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Hypercholesterolemia, autosomal dominant, 3 Uncertain:5
This sequence change replaces serine, which is neutral and polar, with glycine, which is neutral and non-polar, at codon 668 of the PCSK9 protein (p.Ser668Gly). This variant is present in population databases (rs775077080, gnomAD 0.02%). This missense change has been observed in individual(s) with familial hypercholesterolemia (PMID: 33418990, 35913489). ClinVar contains an entry for this variant (Variation ID: 297707). 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 PCSK9 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.
This missense variant replaces serine with glycine at codon 668 of the PCSK9 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 been reported in one individual affected with familial hypercholesterolemia (PMID: 33418990). This variant has been identified in 12/250532 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.
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.
subject mutated among 2600 FH index cases screened = 1, family member = 1 / Software predictions: Benign
not specified Uncertain:1
Variant summary: PCSK9 c.2002A>G (p.Ser668Gly) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. The variant allele was found at a frequency of 2.5e-05 in 1613848 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in PCSK9 causing Familial Hypercholesterolemia (2.5e-05 vs 3.8e-05), allowing no conclusion about variant significance. c.2002A>G has been observed in individual(s) affected with Familial Hypercholesterolemia, without strong evidence for causality (e.g. Meshkov_2021, Sustar_2022, Ferch_2025). These report(s) do not provide unequivocal conclusions about association of the variant with Familial Hypercholesterolemia. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 39535057, 33418990, 35913489). ClinVar contains an entry for this variant (Variation ID: 297707). Based on the evidence outlined above, the variant was classified as uncertain significance.
Hypobetalipoproteinemia 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.
not provided Uncertain:1
The frequency of this variant in the general population, 0.00023 (8/34564 chromosomes in Latino/Admixed American subpopulation, http://gnomad.broadinstitute.org), is higher than would generally be expected for pathogenic variants in this gene. In the published literature, the variant has been reported in an individual with familial hypercholesteremia (PMID: 33418990 (2021)). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is benign. Based on the available information, we are unable to determine the clinical significance of this variant.
Cardiovascular phenotype Uncertain:1
The p.S668G variant (also known as c.2002A>G), located in coding exon 12 of the PCSK9 gene, results from an A to G substitution at nucleotide position 2002. The serine at codon 668 is replaced by glycine, an amino acid with similar properties. An alternate amino acid substitution at this codon, p.S668R, was reported in an individual from a low LDL-C cohort; however, clinical details were limited (Miyake Y et al. Atherosclerosis, 2008 Jan;196:29-36). This amino acid position is not well conserved on limited sequence alignment. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.
Familial hypercholesterolemia Uncertain:1
This missense variant replaces serine with glycine at codon 668 of the PCSK9 protein. Computational prediction suggests that this variant may not impact protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with familial hypercholesterolemia (PMID: 33418990). This variant has been identified in 12/250532 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.
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at