NM_000057.4:c.1315A>G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_000057.4(BLM):c.1315A>G(p.Met439Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000124 in 1,613,970 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 16/22 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. M439I) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00013 ( 1 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:9

Conservation

PhyloP100: -0.0630

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

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=0.0055795014).

BP6

Variant 15-90760688-A-G is Benign according to our data. Variant chr15-90760688-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 127475.We mark this variant Likely_benign, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BLM	NM_000057.4 link	c.1315A>G	p.Met439Val	missense_variant	Exon 7 of 22	ENST00000355112.8	NP_000048.1	P54132

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BLM	ENST00000355112.8 link	c.1315A>G	p.Met439Val	missense_variant	Exon 7 of 22	1	NM_000057.4	ENSP00000347232.3		P54132

Frequencies

GnomAD3 genomes

AF:

0.000105

AC:

AN:

152212

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00317

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000251

AC:

AN:

251248

AF XY:

0.000228

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00467

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000123

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.000126

AC:

184

AN:

1461758

Hom.:

Cov.:

AF XY:

0.000132

AC XY:

AN XY:

727196

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000447

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00452

AC:

118

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53408

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000450

AC:

AN:

1111906

Other (OTH)

AF:

0.000232

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

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:

0.000105

AC:

AN:

152212

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74364

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41448

American (AMR)

AF:

0.000131

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00317

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.497

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:

0.000259

Hom.:

Bravo

AF:

0.000125

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000247

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:9

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Bloom syndrome

Uncertain:2Benign:2

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Jan 17, 2019

Baylor Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Jan 20, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jun 23, 2025

Mendelics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following: it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease, and/or has normal protein function, and/or has lack of segregation with disease, and/or has been detected in co-occurrence with known pathogenic variant, and/or has lack of disease association in case-control studies, and/or is located in a region inconsistent with a known cause of pathogenicity. -

not provided

Uncertain:1Benign:2

Sep 14, 2023

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 16, 2024

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis indicates that this missense variant does not alter protein structure/function; Identified in patients referred for hereditary cancer genetic testing (PMID: 31159747); This variant is associated with the following publications: (PMID: 31159747) -

Aug 01, 2022

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

BLM: BP4 -

Hereditary cancer-predisposing syndrome

Benign:3

Aug 01, 2018

GeneKor MSA

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dec 01, 2020

Sema4, Sema4

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:curation

- -

Oct 30, 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. -

not specified

Benign:2

May 30, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: BLM c.1315A>G (p.Met439Val) results in a conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be tolerated. The variant allele was found at a frequency of 0.00012 in 1613970 control chromosomes, predominantly at a frequency of 0.0044 within the Ashkenazi Jewish subpopulation in the gnomAD database, including 1 homozygote. The observed variant frequency within Ashkenazi Jewish control individuals in the gnomAD database is approximately 1.24 fold of the estimated maximal expected allele frequency for a pathogenic variant in BLM causing Bloom Syndrome phenotype (0.0035). c.1315A>G has been reported as a VUS in at least one individual undergoing multigene panel testing for a suspected hereditary cancer predisposition syndrome (Tsaousis_2019), but to our knowledge has not been observed in individual(s) affected with Bloom Syndrome. This report does not provide unequivocal conclusions about association of the variant with Bloom Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 31159747). ClinVar contains an entry for this variant (Variation ID: 127475). Based on the evidence outlined above, the variant was classified as likely benign. -

Apr 16, 2018

Genetic Services Laboratory, University of Chicago

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.055

BayesDel_addAF

Benign

-0.55

BayesDel_noAF

Benign

-0.79

CADD

Benign

0.064

(source)

DANN

Benign

0.30

DEOGEN2

Benign

0.049

T;.

Eigen

Benign

-1.3

Eigen_PC

Benign

-1.3

FATHMM_MKL

Benign

0.0014

LIST_S2

Benign

0.38

T;T

M_CAP

Benign

0.0081

MetaRNN

Benign

0.0056

T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

-1.4

N;.

PhyloP100

-0.063

PrimateAI

Benign

0.22

PROVEAN

Benign

0.62

N;N

REVEL

Benign

0.076

Sift

Benign

1.0

T;T

Sift4G

Benign

0.43

T;T

Polyphen

0.0

B;.

Vest4

0.028

MVP

0.56

MPC

0.089

ClinPred

0.013

GERP RS

1.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.019

gMVP

0.17

Mutation Taster

=97/3

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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