rs141269464

Positions:

chr15-90798289-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000057.4(BLM):c.3310G>A(p.Gly1104Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000085 in 1,612,676 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/23 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000086 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: 2.78

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:

BLM (HGNC:):

BLM links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BLM	NM_000057.4 linkuse as main transcript	c.3310G>A	p.Gly1104Ser	missense_variant	17/22	ENST00000355112.8	NP_000048.1	P54132

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BLM	ENST00000355112.8 linkuse as main transcript	c.3310G>A	p.Gly1104Ser	missense_variant	17/22	1	NM_000057.4	ENSP00000347232.3		P54132

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152092

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000966

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:

0.000103

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000439

AC:

AN:

250732

Hom.:

AF XY:

0.0000443

AC XY:

AN XY:

135518

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:

0.0000970

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000863

AC:

126

AN:

1460584

Hom.:

Cov.:

AF XY:

0.0000840

AC XY:

AN XY:

726572

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

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:

0.000112

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152092

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74304

show subpopulations

Gnomad4 AFR

AF:

0.0000966

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:

0.000103

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000174

Hom.:

Bravo

AF:

0.0000567

TwinsUK

AF:

0.000539

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000494

AC:

EpiCase

AF:

0.0000546

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Bloom syndrome

Uncertain:3

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Oct 29, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 30, 2024	This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 1104 of the BLM protein (p.Gly1104Ser). This variant is present in population databases (rs141269464, gnomAD 0.01%). 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: 236815). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt BLM protein function with a negative predictive value of 80%. RNA analysis performed to evaluate the impact of this missense change on mRNA splicing indicates it does not significantly alter splicing (Invitae). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	St. Jude Molecular Pathology, St. Jude Children's Research Hospital	May 13, 2024	The BLM cc.3310G>A (p.Gly1104Ser) missense change has a maximum subpopulation frequency of 0.011% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org). The in silico tool REVEL predicts a benign effect of this variant on protein function, and to our knowledge functional studies have not been performed. This variant has been identified in 1 of 1358 control individuals collected as part of non-cancer studies (PMID: 29641532). To our knowledge, this variant has not been reported in individuals with Bloom syndrome. In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Mar 09, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 24, 2022	The p.G1104S variant (also known as c.3310G>A), located in coding exon 16 of the BLM gene, results from a G to A substitution at nucleotide position 3310. The glycine at codon 1104 is replaced by serine, an amino acid with similar properties. This alteration was identified in 1/1358 non-cancer control individuals in a study looking at cancer predisposition mutations in patients with multiple primary cancers (Pritchard AL et al. PLoS ONE, 2018 Apr;13:e0194098). This amino acid position is 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. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Dec 21, 2023

Variant summary: BLM c.3310G>A (p.Gly1104Ser) results in a non-conservative amino acid change located in the RQC domain (IPR018982) of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4.7e-05 in 253448 control chromosomes (gnomAD and Pritchard_2018). This frequency is not significantly higher than estimated for a pathogenic variant in BLM causing Bloom Syndrome (4.7e-05 vs 0.0035), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.3310G>A in individuals affected with Bloom Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. The following publication has been ascertained in the context of this evaluation (PMID: 29641532). Five submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 26, 2019

In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; In silico analysis, which includes splice predictors and evolutionary conservation, suggests this variant may impact gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; This variant is associated with the following publications: (PMID: 29641532, 29643063, 23129629) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.085

BayesDel_addAF

Benign

-0.27

BayesDel_noAF

Benign

-0.43

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Benign

0.10

T;.

Eigen

Benign

-0.11

Eigen_PC

Benign

0.042

FATHMM_MKL

Uncertain

0.87

LIST_S2

Benign

0.83

T;T

M_CAP

Benign

0.0069

MetaRNN

Benign

0.20

T;T

MetaSVM

Benign

-1.1

MutationAssessor

Benign

0.83

L;.

PrimateAI

Benign

0.43

PROVEAN

Benign

-1.2

N;N

REVEL

Benign

0.028

Sift

Benign

0.33

T;T

Sift4G

Benign

0.20

T;T

Polyphen

0.43

B;.

Vest4

0.20

MVP

0.83

MPC

0.10

ClinPred

0.13

GERP RS

4.4

Varity_R

0.088

gMVP

0.61

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.25

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.25

Position offset: -4

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