rs527291754

Positions:

chr15-90811264-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2BP4_StrongBP6

The NM_000057.4(BLM):c.3934G>A(p.Ala1312Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000112 in 1,614,164 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 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. A1312V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000055 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:2

Conservation

PhyloP100: -1.44

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 Likely_benign. Variant got -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.034035295).

BP6

Variant 15-90811264-G-A is Benign according to our data. Variant chr15-90811264-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 127506.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BLM	NM_000057.4 linkuse as main transcript	c.3934G>A	p.Ala1312Thr	missense_variant	21/22	ENST00000355112.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BLM	ENST00000355112.8 linkuse as main transcript	c.3934G>A	p.Ala1312Thr	missense_variant	21/22	1	NM_000057.4	P2

Frequencies

GnomAD3 genomes

AF:

0.0000591

AC:

AN:

152204

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000217

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251440

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135900

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000547

AC:

AN:

1461842

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727226

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152322

Hom.:

Cov.:

AF XY:

0.0000806

AC XY:

AN XY:

74474

show subpopulations

Gnomad4 AFR

AF:

0.000216

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000416

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Bloom syndrome

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Oct 05, 2022	This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 1312 of the BLM protein (p.Ala1312Thr). This variant is present in population databases (rs527291754, gnomAD 0.007%). 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: 127506). 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. 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 provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Feb 20, 2014

Single pathogenic variants in BLM have only recently been described in association with cancer predisposition and the risks are not well understood. This variant is denoted BLM c.3934G>A at the cDNA level, p.Ala1312Thr (A1312T) at the protein level, and results in the change of an Alanine to a Threonine (GCT>ACT). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. BLM Ala1312Thr was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. This variant is a non-conservative substitution in which a neutral non-polar amino acid is replaced with a neutral polar one, altering a position that is highly variable throughout evolution and is not located in a known functional domain. In silico analyses predict this variant to have a benign effect on protein structure and function. On a molecular level, the impact of this missense variant on protein structure and function is not known and thus we consider this to be a variant of uncertain significance. Furthermore, based on the currently available information, cancer risks associated with this variant, and with single variants the BLM gene in general, remain unclear. -

Hereditary cancer-predisposing syndrome

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 20, 2023

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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.065

BayesDel_addAF

Benign

-0.50

BayesDel_noAF

Benign

-0.78

CADD

Benign

0.13

DANN

Benign

0.73

DEOGEN2

Benign

0.066

T;.

Eigen

Benign

-1.9

Eigen_PC

Benign

-2.0

FATHMM_MKL

Benign

0.0086

LIST_S2

Benign

0.16

T;T

M_CAP

Benign

0.0087

MetaRNN

Benign

0.034

T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

0.69

N;.

MutationTaster

Benign

1.0

N;N

PrimateAI

Benign

0.24

PROVEAN

Benign

-0.070

N;N

REVEL

Benign

0.017

Sift

Benign

0.35

T;T

Sift4G

Benign

0.62

T;T

Polyphen

0.0

B;.

Vest4

0.034

MutPred

0.15

Gain of phosphorylation at A1312 (P = 0.0063);.;

MVP

0.52

MPC

0.085

ClinPred

0.044

GERP RS

-7.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.021

gMVP

0.16

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

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