rs753635754

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3_Moderate

The NM_000057.4(BLM):​c.2351A>G​(p.Tyr784Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000682 in 1,613,838 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y784N) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

3
9
7

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 7.13

Publications

3 publications found
Variant links:
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]
BLM Gene-Disease associations (from GenCC):
  • Bloom syndrome
    Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Myriad Women’s Health, Labcorp Genetics (formerly Invitae), G2P, Laboratory for Molecular Medicine, Orphanet, Genomics England PanelApp, ClinGen
  • osteosarcoma
    Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
  • breast cancer
    Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
  • hereditary nonpolyposis colon cancer
    Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PP3
MetaRNN computational evidence supports a deleterious effect, 0.849

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
BLMNM_000057.4 linkc.2351A>G p.Tyr784Cys missense_variant Exon 11 of 22 ENST00000355112.8 NP_000048.1 P54132

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
BLMENST00000355112.8 linkc.2351A>G p.Tyr784Cys missense_variant Exon 11 of 22 1 NM_000057.4 ENSP00000347232.3 P54132

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152248
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000159
AC:
4
AN:
251474
AF XY:
0.0000147
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000264
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000616
AC:
9
AN:
1461590
Hom.:
0
Cov.:
32
AF XY:
0.00000550
AC XY:
4
AN XY:
727122
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33472
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39694
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86248
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53418
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.00000720
AC:
8
AN:
1111746
Other (OTH)
AF:
0.00
AC:
0
AN:
60388
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.503
Heterozygous variant carriers
0
1
2
3
4
5
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000131
AC:
2
AN:
152248
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74368
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41464
American (AMR)
AF:
0.00
AC:
0
AN:
15288
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5202
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10616
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68050
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.0000487
Hom.:
0
Bravo
AF:
0.00000756

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Bloom syndrome Uncertain:3
Jul 25, 2021
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Nov 19, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 784 of the BLM protein (p.Tyr784Cys). This variant is present in population databases (no rsID available, gnomAD 0.005%). 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: 454100). 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 expected to disrupt BLM protein function with a positive predictive value of 80%. 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. -

Sep 16, 2020
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:2
Jan 15, 2025
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.Y784C variant (also known as c.2351A>G), located in coding exon 10 of the BLM gene, results from an A to G substitution at nucleotide position 2351. The tyrosine at codon 784 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is highly 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. -

Sep 15, 2021
Sema4, Sema4
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:curation

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.27
BayesDel_addAF
Benign
-0.041
T
BayesDel_noAF
Benign
-0.13
CADD
Pathogenic
27
DANN
Uncertain
1.0
DEOGEN2
Benign
0.30
T;.
Eigen
Uncertain
0.67
Eigen_PC
Uncertain
0.66
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Uncertain
0.95
D;D
M_CAP
Benign
0.037
D
MetaRNN
Pathogenic
0.85
D;D
MetaSVM
Benign
-1.0
T
MutationAssessor
Uncertain
2.3
M;.
PhyloP100
7.1
PrimateAI
Uncertain
0.62
T
PROVEAN
Pathogenic
-8.3
D;D
REVEL
Uncertain
0.36
Sift
Uncertain
0.0020
D;D
Sift4G
Uncertain
0.0040
D;D
Polyphen
0.96
D;.
Vest4
0.94
MutPred
0.54
Gain of catalytic residue at K787 (P = 0.1174);Gain of catalytic residue at K787 (P = 0.1174);
MVP
0.85
MPC
0.53
ClinPred
0.99
D
GERP RS
5.4
Varity_R
0.91
gMVP
0.88
Mutation Taster
=19/81
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.010
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs753635754; hg19: chr15-91312406; API