rs762267785

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_000057.4(BLM):c.2822A>G(p.Gln941Arg) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000186 in 1,613,988 control chromosomes in the GnomAD database, with no homozygous occurrence. 2/2 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q941H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000018 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense, splice_region

Scores

Splicing: ADA: 0.9999

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 9.21

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BLM	NM_000057.4 linkuse as main transcript	c.2822A>G	p.Gln941Arg	missense_variant, splice_region_variant	14/22	ENST00000355112.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BLM	ENST00000355112.8 linkuse as main transcript	c.2822A>G	p.Gln941Arg	missense_variant, splice_region_variant	14/22	1	NM_000057.4	P2

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152212

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251268

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135828

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000178

AC:

AN:

1461776

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

727190

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000225

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152212

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74366

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000574

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Bloom syndrome

Uncertain:2

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 18, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Oct 13, 2022	This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 941 of the BLM protein (p.Gln941Arg). This variant is present in population databases (rs762267785, gnomAD 0.003%). 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: 236806). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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 specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Feb 15, 2021

DNA sequence analysis of the BLM gene demonstrated a sequence change, c.2822A>G, in exon 14 that results in an amino acid change, p.Gln941Arg. This sequence change has been described in gnomAD with a low population frequency of 0.0014% (dbSNP rs762267785). The p.Gln941Arg change affects a moderately conserved amino acid residue located in a domain of the BLM protein that is known to be functional. The p.Gln941Arg substitution appears to be benign using several in-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL). This sequence change does not appear to have been previously described in patients with BLM-related disorders. Due to the lack of sufficient evidences, the clinical significance of the p.Gln941Arg change remains unknown at this time. -

Hereditary cancer-predisposing syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 09, 2024

The p.Q941R variant (also known as c.2822A>G), located in coding exon 13 of the BLM gene, results from an A to G substitution at nucleotide position 2822. The glutamine at codon 941 is replaced by arginine, an amino acid with highly similar properties. This alteration was identified in 1/1358 non-cancer control individuals and in 0/57 cases, in a study looking at cancer predisposition mutations in patients with cutaneous melanoma and a history of at least two additional non-cutaneous melanoma primary cancers (Pritchard AL et al. PLoS One, 2018 Apr;13:e0194098). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Uncertain

0.12

BayesDel_noAF

Uncertain

0.0

Cadd

Pathogenic

Dann

Uncertain

1.0

DEOGEN2

Benign

0.26

T;.

Eigen

Benign

0.18

Eigen_PC

Uncertain

0.38

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.92

D;D

M_CAP

Benign

0.061

MetaRNN

Uncertain

0.69

D;D

MetaSVM

Benign

-0.54

MutationAssessor

Benign

0.36

N;.

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.79

PROVEAN

Benign

-1.9

N;N

REVEL

Uncertain

0.44

Sift

Benign

0.18

T;T

Sift4G

Benign

0.090

T;T

Polyphen

0.42

B;.

Vest4

0.80

MutPred

0.50

Loss of catalytic residue at C940 (P = 0.2628);Loss of catalytic residue at C940 (P = 0.2628);

MVP

0.89

MPC

0.49

ClinPred

0.59

GERP RS

5.8

Varity_R

0.55

gMVP

0.88

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

1.0

SpliceAI score (max)

0.16

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over