chr1-55043958-T-G
Variant summary
Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2PM5PP3_ModeratePP5
The NM_174936.4(PCSK9):c.323T>G(p.Leu108Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,880 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L108P) has been classified as Pathogenic.
Frequency
Consequence
NM_174936.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 33
GnomAD4 exome AF: 6.84e-7 AC: 1AN: 1461880Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 727238
GnomAD4 genome Cov.: 33
ClinVar
Submissions by phenotype
Hypercholesterolemia, autosomal dominant, 3 Pathogenic:2
subject mutated among 2600 FH index cases screened = 1, family member = 1 / functionnal testing (PMID:22683120) / Software predictions: Benign -
This sequence change replaces leucine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 108 of the PCSK9 protein (p.Leu108Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with familial hypercholesterolemia (PMID: 22683120; Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 375849). 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 80%. Experimental studies have shown that this missense change affects PCSK9 function (PMID: 22683120, 26195630, 29259136, 34948399). For these reasons, this variant has been classified as Pathogenic. -
Familial hypercholesterolemia Pathogenic:1Uncertain:1
The p.Leu108Arg variant in PCSK9 has been reported in 5 individuals with familial hypercholesterolemia, segregated with disease in 4 affected relatives from 1 family (PMID: 26374825, 22683120), and was absent from large population studies. This variant has also been reported in ClinVar as likely pathogenic and pathogenic (Variation ID: 375849). In vitro functional studies provide some evidence that the p.Leu108Arg variant may slightly impact protein function (PMID: 22683120). However, these types of assays may not accurately represent biological function. Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. In summary, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PM2, PP1, PS4_supporting, PS3_supporting (Richards 2015). -
Variant summary: The PCSK9 c.323T>G (p.Leu108Arg) variant involves the alteration of a non-conserved nucleotide. 3/4 in silico tools predict a damaging outcome for this variant. This variant is absent in 121160 control chromosomes. This variant has been reported in one FH family with unequivocal co-segregation evidence (found in 4 affected members, not found in 3 unaffected members). In vitro study showed that p.L108R had a clear and significant gain-of-function effect. Taken together, this variant is classified as likely pathogenic until additional FH families are reported to carry this variant. -
Cardiovascular phenotype Uncertain:1
The p.L108R variant (also known as c.323T>G), located in coding exon 2 of the PCSK9 gene, results from a T to G substitution at nucleotide position 323. The leucine at codon 108 is replaced by arginine, an amino acid with dissimilar properties. This variant was identified in one or more individuals with features consistent with familial hypercholesterolemia (FH) and segregated with disease in at least one family (Abifadel M et al. Atherosclerosis, 2012 Aug;223:394-400; Rimbert A et al. Front Genet, 2021 Jan;12:809256; Razman AZ et al. Int J Mol Sci, 2022 Nov;23:[ePub ahead of print]). 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. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at