Genetic Variant BLM:p.Leu60Ile (chr15-90749446-T-A) – ACMG Classification: Benign (-13 pts)

Variant summary

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

The NM_000057.4(BLM):c.178T>A(p.Leu60Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000158 in 1,612,296 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00014 ( 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:3B:7O:1

Conservation

PhyloP100: 0.226

Publications

8 publications found

Variant links:

COSMIC-nc: COSV105909954

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: Orphanet, Labcorp Genetics (formerly Invitae), G2P, Myriad Women’s Health, Genomics England PanelApp, ClinGen, Laboratory for Molecular Medicine
osteosarcoma
Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
colorectal cancer
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
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: Benign. The variant received -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.0064494014).

BP6

Variant 15-90749446-T-A is Benign according to our data. Variant chr15-90749446-T-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 133710.

BS1

Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.000138 (21/152316) while in subpopulation EAS AF = 0.00405 (21/5180). AF 95% confidence interval is 0.00272. There are 0 homozygotes in GnomAd4. There are 15 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

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	UniProt
BLM	NM_000057.4	MANE Select	c.178T>A	p.Leu60Ile	missense	Exon 3 of 22	NP_000048.1	P54132
BLM	NM_001287246.2		c.178T>A	p.Leu60Ile	missense	Exon 4 of 23	NP_001274175.1	P54132
BLM	NM_001287247.2		c.178T>A	p.Leu60Ile	missense	Exon 3 of 20	NP_001274176.1	H0YNU5

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
BLM	ENST00000355112.8	TSL:1 MANE Select	c.178T>A	p.Leu60Ile	missense	Exon 3 of 22	ENSP00000347232.3	P54132
BLM	ENST00000560509.5	TSL:1	c.178T>A	p.Leu60Ile	missense	Exon 3 of 20	ENSP00000454158.1	H0YNU5
BLM	ENST00000559724.5	TSL:1	n.178T>A		non_coding_transcript_exon	Exon 3 of 22	ENSP00000453359.1	H0YLV8

Frequencies

GnomAD3 genomes

AF:

0.000138

AC:

AN:

152198

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:

0.00404

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:

0.000264

AC:

AN:

250406

AF XY:

0.000280

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00343

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000177

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.000160

AC:

234

AN:

1459980

Hom.:

Cov.:

AF XY:

0.000180

AC XY:

131

AN XY:

726484

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33434

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26120

East Asian (EAS)

AF:

0.00572

AC:

227

AN:

39682

South Asian (SAS)

AF:

0.00

AC:

AN:

86228

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53414

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1110290

Other (OTH)

AF:

0.000116

AC:

AN:

60328

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

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:

0.000138

AC:

AN:

152316

Hom.:

Cov.:

AF XY:

0.000201

AC XY:

AN XY:

74480

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41568

American (AMR)

AF:

0.00

AC:

AN:

15308

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00405

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

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:

0.000303

Hom.:

Bravo

AF:

0.000136

ExAC

AF:

0.000313

AC:

Asia WGS

AF:

0.00173

AC:

AN:

3478

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Bloom syndrome (3)

Hereditary cancer-predisposing syndrome (2)

not specified (3)

BLM-related disorder (1)

Hereditary breast ovarian cancer syndrome (1)

Microcephaly (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.10

BayesDel_addAF

Benign

-0.41

BayesDel_noAF

Benign

-0.36

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.29

Eigen

Benign

-0.044

Eigen_PC

Benign

-0.25

FATHMM_MKL

Benign

0.18

LIST_S2

Benign

0.75

M_CAP

Benign

0.062

MetaRNN

Benign

0.0064

MetaSVM

Benign

-0.81

MutationAssessor

Uncertain

2.4

PhyloP100

0.23

PrimateAI

Benign

0.43

PROVEAN

Benign

-0.90

REVEL

Benign

0.099

Sift

Pathogenic

0.0

Sift4G

Benign

0.12

Polyphen

0.99

Vest4

0.25

MVP

0.83

MPC

0.15

ClinPred

0.12

GERP RS

0.57

Varity_R

0.43

gMVP

0.049

Mutation Taster

=98/2

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

Computational scores

Splicing

Publications

Other links and lift over