rs192491153

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBS1_Supporting

The NM_000057.4(BLM):c.1519G>A(p.Glu507Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000217 in 1,613,888 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign 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. E507G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00014 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:1

Conservation

PhyloP100: 3.20

Publications

2 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

BLM links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.02783683).

BS1

Variant frequency is greater than expected in population amr. GnomAd4 allele frequency = 0.000138 (21/152156) while in subpopulation AMR AF = 0.00131 (20/15274). AF 95% confidence interval is 0.000867. There are 0 homozygotes in GnomAd4. There are 11 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BLM	NM_000057.4 link	c.1519G>A	p.Glu507Lys	missense_variant	Exon 7 of 22	ENST00000355112.8	NP_000048.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BLM	ENST00000355112.8 link	c.1519G>A	p.Glu507Lys	missense_variant	Exon 7 of 22	1	NM_000057.4	ENSP00000347232.3

Frequencies

GnomAD3 genomes

AF:

0.000138

AC:

AN:

152038

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00131

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000160

AC:

AN:

250418

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.00000958

AC:

AN:

1461732

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

727170

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000894

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53276

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1112006

Other (OTH)

AF:

0.000132

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.471

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<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:

0.000138

AC:

AN:

152156

Hom.:

Cov.:

AF XY:

0.000148

AC XY:

AN XY:

74394

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41506

American (AMR)

AF:

0.00131

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10580

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68004

Other (OTH)

AF:

0.00

AC:

AN:

2106

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.535

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<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:

0.00

Hom.:

Bravo

AF:

0.000238

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Apr 23, 2024

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis indicates that this missense variant does not alter protein structure/function; Observed in an individual with breast cancer (PMID: 31780696); This variant is associated with the following publications: (PMID: 31780696) -

Mar 21, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The BLM c.1519G>A (p.Glu507Lys) variant has been reported in the published literature in an individual with breast cancer (PMID: 31780696 (2019)). The frequency of this variant in the general population, 0.000087 (3/34572 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 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

Uncertain:1Benign:1

Mar 26, 2018

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. -

Oct 25, 2021

Sema4, Sema4

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:curation

- -

not specified

Uncertain:1

Oct 01, 2021

Genetic Services Laboratory, University of Chicago

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

DNA sequence analysis of the BLM gene demonstrated a sequence change, c.1519G>A, in exon 7 that results in an amino acid change, p.Glu507Lys. This sequence change has been described in the gnomAD database with a frequency of 0.0087% in the Latino/Admixed American subpopulation (dbSNP rs192491153). The p.Glu507Lys change affects a moderately conserved amino acid residue located in a domain of the BLM protein that is not known to be functional. The p.Glu507Lys substitution appears to be benign using several in-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL). This sequence change has previously been described in an individual with breast cancer (PMID: 31780696). Due to insufficient evidence and the lack of functional studies, the clinical significance of the p.Glu507Lys change remains unknown at this time. -

Bloom syndrome

Uncertain:1

Jan 28, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 507 of the BLM protein (p.Glu507Lys). This variant is present in population databases (rs192491153, gnomAD 0.006%). This missense change has been observed in individual(s) with breast cancer (PMID: 31780696). ClinVar contains an entry for this variant (Variation ID: 405326). 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 not expected to disrupt BLM protein function with a negative 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.086

BayesDel_addAF

Benign

-0.24

BayesDel_noAF

Benign

-0.41

CADD

Benign

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.13

T;.

Eigen

Benign

0.023

Eigen_PC

Benign

0.13

FATHMM_MKL

Uncertain

0.87

LIST_S2

Benign

0.78

T;T

M_CAP

Benign

0.018

MetaRNN

Benign

0.028

T;T

MetaSVM

Benign

-0.98

MutationAssessor

Uncertain

2.1

M;.

PhyloP100

3.2

PrimateAI

Benign

0.34

PROVEAN

Benign

-0.62

N;N

REVEL

Benign

0.064

Sift

Benign

0.039

D;D

Sift4G

Benign

0.65

T;T

Polyphen

0.79

P;.

Vest4

0.29

MVP

0.80

MPC

0.15

ClinPred

0.12

GERP RS

4.9

Varity_R

0.085

gMVP

0.68

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over