chr15-90790664-A-G

Variant names:

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_000057.4(BLM):c.2839A>G(p.Ile947Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000159 in 1,614,154 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 17/22 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. I947T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00016 ( 2 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:4

Conservation

PhyloP100: 3.52

Publications

9 publications found

Variant links:

COSMIC-nc: COSV105909991

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:

ENSG00000300894 (HGNC:):

ENSG00000300894 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.018725693).

BP6

Variant 15-90790664-A-G is Benign according to our data. Variant chr15-90790664-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 454121.

BS1

Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.000118 (18/152314) while in subpopulation EAS AF = 0.00309 (16/5180). AF 95% confidence interval is 0.00194. There are 0 homozygotes in GnomAd4. There are 9 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High Homozygotes in GnomAdExome4 at 2 AR,AD gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BLM	NM_000057.4 link	c.2839A>G	p.Ile947Val	missense_variant	Exon 15 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.2839A>G	p.Ile947Val	missense_variant	Exon 15 of 22	1	NM_000057.4	ENSP00000347232.3		P54132

Frequencies

GnomAD3 genomes

AF:

0.000118

AC:

AN:

152196

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00308

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000207

AC:

AN:

251454

AF XY:

0.000169

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00266

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000163

AC:

238

AN:

1461840

Hom.:

Cov.:

AF XY:

0.000155

AC XY:

113

AN XY:

727214

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00554

AC:

220

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000126

AC:

AN:

1111988

Other (OTH)

AF:

0.0000662

AC:

AN:

60386

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.487

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:

0.000118

AC:

AN:

152314

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74484

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41582

American (AMR)

AF:

0.0000653

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00309

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

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:

0.000202

Hom.:

Bravo

AF:

0.000125

ExAC

AF:

0.000222

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Bloom syndrome

Uncertain:1Benign:1

Jan 29, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Hereditary cancer-predisposing syndrome

Uncertain:1Benign:1

Jul 01, 2021

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. -

Jul 21, 2021

Sema4, Sema4

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:curation

- -

not specified

Uncertain:1

Feb 24, 2022

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: BLM c.2839A>G (p.Ile947Val) results in a conservative amino acid change located in the Helicase, C-terminal domain (IPR001650) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00021 in 251454 control chromosomes, predominantly at a frequency of 0.0027 within the East Asian subpopulation in the gnomAD database. This frequency is not significantly higher than expected for a pathogenic variant in BLM causing Bloom Syndrome (0.00021 vs 0.0035), allowing no conclusion about variant significance. c.2839A>G has been reported in the literature as a VUS in settings of multigene panel testing among individuals affected with/undergoing testing for a variety of cancers (example, Kim_2019, Park_2018, Zhang_2019). These report(s) do 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. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation (Likely benign, n=1; VUS, n=3). Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -

Hereditary breast ovarian cancer syndrome

Uncertain:1

May 01, 2019

Cancer Genomics Group, Japanese Foundation For Cancer Research

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

- -

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

- -

not provided

Benign:1

Sep 26, 2022

Quest Diagnostics Nichols Institute San Juan Capistrano

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

0.076

BayesDel_addAF

Benign

-0.40

BayesDel_noAF

Benign

-0.35

CADD

Benign

(source)

DANN

Benign

0.89

DEOGEN2

Benign

0.33

T;.

Eigen

Benign

-0.80

Eigen_PC

Benign

-0.72

FATHMM_MKL

Uncertain

0.86

LIST_S2

Uncertain

0.90

D;D

M_CAP

Benign

0.017

MetaRNN

Benign

0.019

T;T

MetaSVM

Benign

-0.96

MutationAssessor

Benign

0.41

N;.

PhyloP100

3.5

PrimateAI

Benign

0.47

PROVEAN

Benign

-0.83

N;N

REVEL

Benign

0.11

Sift

Benign

0.068

T;T

Sift4G

Pathogenic

0.0

D;D

Polyphen

0.045

B;.

Vest4

0.24

MVP

0.76

MPC

0.13

ClinPred

0.069

GERP RS

-0.18

Varity_R

0.21

gMVP

0.40

Mutation Taster

=77/23

polymorphism

(source)

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