16-23637951-C-T
Variant summary
Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_001407304.1(PALB2):c.-776G>A variant causes a 5 prime UTR premature start codon gain change. The variant allele was found at a frequency of 0.0000391 in 1,613,090 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 Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_001407304.1 5_prime_UTR_premature_start_codon_gain
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000592 AC: 9AN: 152034Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000398 AC: 10AN: 251458Hom.: 0 AF XY: 0.0000368 AC XY: 5AN XY: 135904
GnomAD4 exome AF: 0.0000376 AC: 55AN: 1460938Hom.: 0 Cov.: 30 AF XY: 0.0000344 AC XY: 25AN XY: 726822
GnomAD4 genome AF: 0.0000526 AC: 8AN: 152152Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74364
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Uncertain:4
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This missense variant replaces arginine with histidine at codon 37 of the PALB2 protein. Computational prediction suggests that this variant may not impact protein structure and function. Functional studies of this variant have demonstrated moderate to low effects on homologous recombination, BRCA1-interaction, RAD51 foci formation, and PARP inhibitor sensitivity (PMID: 28319063, 31586400, 31636395, 31757951, 33195396, 33811135). This variant has been reported in individuals affected with breast, pancreatic, prostate, colorectal and head and neck cancer in the literature (PMID: 22241545, 23935836, 27978560, 28678401, 28779002, 31214711, 33309985, 33471991, 33811135, 36175305). This variant also has been detected in a breast cancer case-control meta-analysis in 5/60466 cases and 2/53461 unaffected individuals (PMID: 33471991; Leiden Open Variation Database DB-ID PALB2_010020). This variant has been identified in 11/282840 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. -
The p.R37H variant (also known as c.110G>A), located in coding exon 3 of the PALB2 gene, results from a G to A substitution at nucleotide position 110. The arginine at codon 37 is replaced by histidine, an amino acid with highly similar properties. One study identified this alteration in 1/565 unilateral breast cancer cases and 0/559 bilateral breast cancer cases (Tischkowitz M et al. Hum. Mutat. 2012 Apr;33:674-80). Another study identified this alteration in 1/132 BRCA1/2-negative Spanish breast/ovarian cancer families with at least one case of pancreatic cancer (Blanco A et al. PLoS ONE. 2013 Jul;8:e67538). This variant has also been identified in 1/450 individuals with early onset colorectal cancer and in 1/417 individuals with head and neck squamous cell carcinoma (Pearlman R et al. JAMA Oncol. 2017 Apr;3:464-471; Chandrasekharappa SC et al. Cancer. 2017 Oct;123:3943-3954). Functional studies demonstrate that this alteration results in mild reduction in homologous repair activity, but it does not affect PALB2-BRCA1 binding and does not confer sensitivity to platinum therapy, mitomycin C, or olaparib therapy, similar to wild-type (Foo TK et al. Oncogene. 2017 Jul;36:4161-4170). Additional studies have shown that this alteration is functionally normal in a homology-directed DNA repair (HDR) assay (Wiltshire T et al. Genet. Med., 2020 03;22:622-632), but is functionally inconclusive in PARPi sensitivity, cisplatin sensitivity, RAD51 foci formation and BRCA1/2 interaction assays (Boonen RACM et al. Nat Commun, 2019 11;10:5296, Rodrigue A et al. Nucleic Acids Res., 2019 11;47:10662-10677). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is still limited at this time, the clinical significance of this alteration remains unclear. -
BP1 c.110G>A, located in exon 3 of the PALB2 gene, is predicted to result in the substitution of arginine by histidine at codon 37, p.(Arg37His). The SpliceAI algorithm predicts no significant impact on splicing and there is a very low likelihood that missense variants are pathogenic in PALB2 (BP1). This variant is found in 3/19250 with a filtering allele frequency of 0.004% (at 95% confidence) in the gnomAD v2.1.1 database (East-Asian non-cancer data set). The variant has been reported in the ClinVar (12x uncertain significance, 1x likely benign) and the LOVD (4x uncertain significance, 4x not classified) databases. Functional studies have been reported for this variant (PMID: 31586400, PMID: 31636395, PMID: 31757951); however, following ClinGen VCEP recommendation, this information cannot be used for variant classification because functional studies have not been validated for PALB2 gene. Based on the currently available information, c.110G>A is classified as an uncertain significance variant according to ClinGen-PALB2 Guidelines version v1.0.0. -
Familial cancer of breast Uncertain:3Benign:1
This variant is considered likely benign. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 25085752]. -
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This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 37 of the PALB2 protein (p.Arg37His). This variant is present in population databases (rs202194596, gnomAD 0.006%). This missense change has been observed in individual(s) with breast cancer, colorectal cancer, prostate cancer, and/or personal or family history of breast and/or ovarian cancer (PMID: 22241545, 23934836, 23935836, 27978560, 28779002, 31214711, 33309985, 36175305). ClinVar contains an entry for this variant (Variation ID: 126590). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on PALB2 function (PMID: 28319063, 31586400, 31636395, 31757951, 33139182, 33195396). 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. -
not provided Uncertain:3
Curators: Marc Tischkowitz, Arleen D. Auerbach. Submitters to LOVD: Marc Tischkowitz, Melissa DeRycke. -
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in individuals with a personal or family history including breast, colorectal, pancreatic, and other cancers (Tischkowitz et al., 2012; Blanco et al., 2013; Decker et al., 2017; Pearlman et al., 2017); This variant is associated with the following publications: (PMID: 27978560, 23935836, 22241545, 28319063, 25428177, 28678401, 28779002, 31757951, 31586400, 31636395, 32209438, 32185139, 33195396, 33169439, 33811135, 33964450, 33139182, 19369211, 20871615) -
The PALB2 c.110G>A (p.Arg37His) variant has been reported in the published literature in individuals affected with breast cancer (PMIDs: 33471991 (2021), 32720237 (2021), 28779002 (2017), 22241545 (2012)), prostate cancer (PMID: 31214711 (2020)), pancreatic (PMID: 36175305 (2022)), and colorectal cancer (PMID: 27978560 (2017)). Additionally, the variant was also reported in reportedly healthy individuals (PMIDs: 33471991 (2021), 28779002 (2017), see also LOVD (http://databases.lovd.nl/shared/genes/PALB2)). Functional studies have reported inconclusive results on the effect this variant has on protein function (PMIDs: 33964450 (2021), 31636395 (2020), 28319063 (2017)). The frequency of this variant in the general population, 0.00015 (3/19952 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
not specified Uncertain:1
Variant summary: PALB2 c.110G>A (p.Arg37His) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant is also located at the second exonic base from a canonical 3' splice acceptor site. 5/5 computational tools predict no significant impact on normal splicing, which is supported by a functional study (Blanco_2013). The variant allele was found at a frequency of 4e-05 in 251458 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in PALB2 causing Hereditary Breast and Ovarian Cancer (4e-05 vs 0.00016), allowing no conclusion about variant significance. c.110G>A has been reported in the literature in sequencing studies of individuals from BRCA families with at-least once case of pancreatic cancer (Blanco_2013); Head and Neck Squamous Cell Carcinoma (HNSCC) (Chandrashekarappa_2017); colorectal cancer (Pearlman_2016); and unilateral breast cancer (Tischkowitz_2012). A systematic review summarizing the earlier reports indicated this variant as not having co-segregated with disease along with a predicted pathogenicity assignment of VUS (Zhan_2018). Therefore, these report(s) do not provide unequivocal conclusions about association of the variant with Hereditary Breast and Ovarian Cancer. Several publications report conflicting experimental evidence evaluating an impact on the various protein functions examined. While the most pronounced variant effect results in 30%-50% of normal activity in HDR assays (Rodrigue_2019 and Boonen_2019), conflicting results resulting in 50-90% of normal activity in HDR assays have also been reported (Foo_2017 and Wiltshire_2019). The results from the ability of this variant to recruit PALB2 to DNA damage sites report conflicting findings ranging from no effect (Foo_2017, Rodrigue_2019) versus an impaired effect (estimated at 54% of WT, Boonen_2019). Ability to form RAD51C foci also exhibited inter-assay variability ranging from no effect (Foo_2017) to a slightly compromised level estimated at 71% of WT (Rodrigue_2019). Lastly, moderate but statistically significant levels of sensitivity to PARP inhibitors such as Olaparib were reported in two studies (Rodrigue_2019 and Boonen_2019). In summary, an unequivocal correlation of these experimental reports to the in-vivo impact of this variant cannot be established from the findings reviewed. Seven clinical diagnostic laboratories and the LOVD have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All submitters classified the variant as uncertain significance some citing overlapping evidence utilized in the context of this evaluation. Based on the reviewed evidence outlined above, the variant retained its classification as uncertain significance. -
Familial cancer of breast;C1835817:Fanconi anemia complementation group N;C3150547:Pancreatic cancer, susceptibility to, 3 Uncertain:1
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PALB2-related disorder Uncertain:1
The PALB2 c.110G>A variant is predicted to result in the amino acid substitution p.Arg37His. This variant has been observed in individuals with a history of breast/ovarian and colorectal cancer (Blanco et al. 2013. PubMed ID: 23935836; Pearlman et al. 2017. PubMed ID: 27978560). However, it has also been reported in control cohorts (Supplementary Table S1, Tischkowitz et al. 2012. PubMed ID: 22241545). In vitro functional studies support that this variant does not impact BRCA1 protein interactions but does reduce PALB2 homologous recombination repair activity (Foo et al. 2017. PubMed ID: 28319063). This variant is reported in 0.015% of alleles in individuals of East Asian descent in gnomAD and has conflicting interpretation in ClinVar ranging from uncertain to likely benign (https://www.ncbi.nlm.nih.gov/clinvar/variation/126590/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at