rs775005766
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Variant summary
Our verdict is Benign. Variant got -8 ACMG points: 0P and 8B. BP4_StrongBS2
The NM_001287248.2(BLM):c.-405A>G variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000347 in 1,612,962 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000037 ( 2 hom. )
Consequence
BLM
NM_001287248.2 5_prime_UTR_premature_start_codon_gain
NM_001287248.2 5_prime_UTR_premature_start_codon_gain
Scores
2
17
Clinical Significance
Conservation
PhyloP100: 0.235
Genes affected
BLM (HGNC:1058): (BLM RecQ like helicase) The Bloom syndrome is an autosomal recessive disorder characterized by growth deficiency, microcephaly and immunodeficiency among others. It is caused by homozygous or compound heterozygous mutation in the gene encoding DNA helicase RecQ protein on chromosome 15q26. This Bloom-associated helicase unwinds a variety of DNA substrates including Holliday junction, and is involved in several pathways contributing to the maintenance of genome stability. Identification of pathogenic Bloom variants is required for heterozygote testing in at-risk families. [provided by RefSeq, May 2020]
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ACMG classification
Classification made for transcript
Verdict is Benign. Variant got -8 ACMG points.
BP4
Computational evidence support a benign effect (MetaRNN=0.038859308).
BS2
High Homozygotes in GnomAdExome4 at 2 AR gene
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
BLM | NM_000057.4 | c.887A>G | p.Tyr296Cys | missense_variant | 4/22 | ENST00000355112.8 | NP_000048.1 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
BLM | ENST00000355112.8 | c.887A>G | p.Tyr296Cys | missense_variant | 4/22 | 1 | NM_000057.4 | ENSP00000347232.3 |
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152230Hom.: 0 Cov.: 32
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GnomAD3 exomes AF: 0.0000836 AC: 21AN: 251272Hom.: 0 AF XY: 0.000125 AC XY: 17AN XY: 135816
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GnomAD4 exome AF: 0.0000370 AC: 54AN: 1460614Hom.: 2 Cov.: 30 AF XY: 0.0000537 AC XY: 39AN XY: 726678
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GnomAD4 genome AF: 0.0000131 AC: 2AN: 152348Hom.: 0 Cov.: 32 AF XY: 0.0000268 AC XY: 2AN XY: 74512
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ClinVar
Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:3Benign:1
Revision: criteria provided, conflicting classifications
LINK: link
Submissions by phenotype
not specified Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Genetic Services Laboratory, University of Chicago | May 03, 2021 | DNA sequence analysis of the BLM gene demonstrated a sequence change, c.887A>G, in exon 4 that results in an amino acid change, p.Tyr296Cys. This sequence change has been described in gnomAD with a frequency of 0.069% in the South Asian sub-population (dbSNP rs775005766). The p.Tyr296Cys change affects a poorly conserved amino acid residue located in a domain of the BLM protein that is not known to be functional. The p.Tyr296Cys substitution appears to be benign using several in-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL). This sequence change does not appear to have been previously described in patients with BLM-related disorders. Due to the lack of sufficient evidences, the clinical significance of the p.Tyr296Cys change remains unknown at this time. - |
Bloom syndrome Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Labcorp Genetics (formerly Invitae), Labcorp | Oct 21, 2022 | This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 296 of the BLM protein (p.Tyr296Cys). This variant is present in population databases (rs775005766, gnomAD 0.07%). This variant has not been reported in the literature in individuals affected with BLM-related conditions. ClinVar contains an entry for this variant (Variation ID: 405307). 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 BLM protein function. 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:1
Uncertain significance, criteria provided, single submitter | clinical testing | Quest Diagnostics Nichols Institute San Juan Capistrano | Oct 27, 2022 | To the best of our knowledge, the variant has not been reported in the published literature. The frequency of this variant in the general population, 0.00069 (21/30608 chromosomes in South Asian subpopulation, http://gnomad.broadinstitute.org), is higher than would generally be expected for pathogenic variants in this gene. 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. - |
Hereditary cancer-predisposing syndrome Benign:1
Likely benign, criteria provided, single submitter | clinical testing | Ambry Genetics | Jun 28, 2022 | This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
BayesDel_addAF
Benign
T
BayesDel_noAF
Benign
CADD
Benign
DANN
Uncertain
DEOGEN2
Benign
T;.
Eigen
Benign
Eigen_PC
Benign
FATHMM_MKL
Benign
N
LIST_S2
Benign
T;T
M_CAP
Benign
T
MetaRNN
Benign
T;T
MetaSVM
Benign
T
MutationAssessor
Uncertain
M;.
PrimateAI
Benign
T
PROVEAN
Benign
N;N
REVEL
Benign
Sift
Benign
T;T
Sift4G
Benign
T;T
Polyphen
B;.
Vest4
MutPred
Loss of phosphorylation at Y296 (P = 0.0046);Loss of phosphorylation at Y296 (P = 0.0046);
MVP
MPC
ClinPred
T
GERP RS
RBP_binding_hub_radar
RBP_regulation_power_radar
Varity_R
gMVP
Splicing
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SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at