NM_000057.4:c.3948C>A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2BP4_ModerateBP6

The NM_000057.4(BLM):c.3948C>A(p.Asp1316Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,964 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. D1316N) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: -2.24

Publications

1 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:

ENSG00000287061 (HGNC:):

ENSG00000287061 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.072233826).

BP6

Variant 15-90811278-C-A is Benign according to our data. Variant chr15-90811278-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1361580.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000057.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
BLM	NM_000057.4	MANE Select	c.3948C>A	p.Asp1316Glu	missense	Exon 21 of 22	NP_000048.1
BLM	NM_001287246.2		c.3948C>A	p.Asp1316Glu	missense	Exon 22 of 23	NP_001274175.1
BLM	NM_001287247.2		c.3555C>A	p.Asp1185Glu	missense	Exon 19 of 20	NP_001274176.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
BLM	ENST00000355112.8	TSL:1 MANE Select	c.3948C>A	p.Asp1316Glu	missense	Exon 21 of 22	ENSP00000347232.3
BLM	ENST00000560509.5	TSL:1	c.3555C>A	p.Asp1185Glu	missense	Exon 19 of 20	ENSP00000454158.1
BLM	ENST00000559724.5	TSL:1	n.*2872C>A		non_coding_transcript_exon	Exon 21 of 22	ENSP00000453359.1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152082

Hom.:

Cov.:

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:

0.00

Gnomad OTH

AF:

0.000481

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251424

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461882

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727240

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

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:

0.00000658

AC:

AN:

152082

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74280

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41404

American (AMR)

AF:

0.00

AC:

AN:

15254

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.000481

AC:

AN:

2080

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

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:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Bloom syndrome

Uncertain:1

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with glutamic acid, which is acidic and polar, at codon 1316 of the BLM protein (p.Asp1316Glu). This variant is present in population databases (rs375896520, gnomAD no frequency). 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: 1361580). 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.

not provided

Uncertain:1

Jul 05, 2023

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 supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

Hereditary cancer-predisposing syndrome

Uncertain:1

Mar 16, 2024

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.D1316E variant (also known as c.3948C>A), located in coding exon 20 of the BLM gene, results from a C to A substitution at nucleotide position 3948. The aspartic acid at codon 1316 is replaced by glutamic acid, an amino acid with highly similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Ovarian cancer

Benign:1

Jan 01, 2022

Laboratory of Molecular Epidemiology of Birth Defects, West China Second University Hospital, Sichuan University

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.078

BayesDel_addAF

Benign

-0.33

BayesDel_noAF

Benign

-0.72

CADD

Benign

0.0020

(source)

DANN

Benign

0.80

DEOGEN2

Benign

0.096

Eigen

Benign

-1.6

Eigen_PC

Benign

-1.7

FATHMM_MKL

Benign

0.014

LIST_S2

Benign

0.47

M_CAP

Benign

0.0075

MetaRNN

Benign

0.072

MetaSVM

Benign

-1.1

MutationAssessor

Benign

1.1

PhyloP100

-2.2

PrimateAI

Benign

0.28

PROVEAN

Benign

-1.1

REVEL

Benign

0.020

Sift

Benign

0.40

Sift4G

Benign

0.48

Polyphen

0.0010

Vest4

0.053

MutPred

0.23

Gain of sheet (P = 0.0125)

MVP

0.45

MPC

0.083

ClinPred

0.040

GERP RS

-10

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.026

gMVP

0.10

Mutation Taster

=93/7

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over