NM_000057.4:c.1933C>T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PVS1PS3PP5_Very_Strong

The NM_000057.4(BLM):c.1933C>T(p.Gln645*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000986 in 1,613,318 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000694474: A functional study showed that in two homozygotes with this variant the signal from the mRNA detected in the Bloom Syndrome cell line was less than 20% of the signal detected in the mRNA from a normal cell line (German_2007)." and additional evidence is available in ClinVar. Synonymous variant affecting the same amino acid position (i.e. Q645Q) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000079 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00010 ( 0 hom. )

Consequence

BLM
NM_000057.4 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:13

Conservation

PhyloP100: 1.67

Publications

14 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: 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: Pathogenic. The variant received 20 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PS3

PS3 evidence extracted from ClinVar submissions: SCV000694474: A functional study showed that in two homozygotes with this variant the signal from the mRNA detected in the Bloom Syndrome cell line was less than 20% of the signal detected in the mRNA from a normal cell line (German_2007).; SCV004222440: Functional studies also show that this variant fails to suppress a downstream factor that promotes tumorigenesis (PMID: 30044990 (2018)).

PP5

Variant 15-90763016-C-T is Pathogenic according to our data. Variant chr15-90763016-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 454091.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.1933C>T	p.Gln645*	stop_gained	Exon 8 of 22	NP_000048.1	P54132
BLM	NM_001287246.2		c.1933C>T	p.Gln645*	stop_gained	Exon 9 of 23	NP_001274175.1	P54132
BLM	NM_001287247.2		c.1933C>T	p.Gln645*	stop_gained	Exon 8 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.1933C>T	p.Gln645*	stop_gained	Exon 8 of 22	ENSP00000347232.3	P54132
BLM	ENST00000560509.5	TSL:1	c.1933C>T	p.Gln645*	stop_gained	Exon 8 of 20	ENSP00000454158.1	H0YNU5
BLM	ENST00000559724.5	TSL:1	n.*857C>T		non_coding_transcript_exon	Exon 8 of 22	ENSP00000453359.1	H0YLV8

Frequencies

GnomAD3 genomes

AF:

0.0000789

AC:

AN:

152096

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:

0.000176

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000439

AC:

AN:

250330

AF XY:

0.0000443

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:

0.0000970

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000101

AC:

147

AN:

1461222

Hom.:

Cov.:

AF XY:

0.000110

AC XY:

AN XY:

726870

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33406

American (AMR)

AF:

0.00

AC:

AN:

44554

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26114

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86054

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.000130

AC:

144

AN:

1111866

Other (OTH)

AF:

0.0000497

AC:

AN:

60372

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

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:

0.0000789

AC:

AN:

152096

Hom.:

Cov.:

AF XY:

0.000108

AC XY:

AN XY:

74272

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41432

American (AMR)

AF:

0.00

AC:

AN:

15260

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10592

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000176

AC:

AN:

68004

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

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:

0.000139

Hom.:

Bravo

AF:

0.0000604

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000233

AC:

ExAC

AF:

0.0000412

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

ClinVar submissions

Significance:Pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Bloom syndrome (6)

not provided (5)

BLM-related disorder (1)

Hereditary cancer-predisposing syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.49

BayesDel_noAF

Pathogenic

0.59

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

0.86

Eigen_PC

Pathogenic

0.71

FATHMM_MKL

Uncertain

0.96

PhyloP100

1.7

Vest4

0.94

GERP RS

4.5

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.17

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