15-90749964-C-A

Position:

chr15-90749964-C-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000057.4(BLM):c.696C>A(p.Ser232Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000217 in 1,614,112 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/21 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 0.000026 ( 1 hom., cov: 32)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:1

Conservation

PhyloP100: -2.18

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 Likely_benign. Variant got -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.057378083).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BLM	NM_000057.4 linkuse as main transcript	c.696C>A	p.Ser232Arg	missense_variant	3/22	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.696C>A	p.Ser232Arg	missense_variant	3/22	1	NM_000057.4	ENSP00000347232.3		P54132

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152234

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:

0.0000441

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.0000478

AC:

AN:

251142

Hom.:

AF XY:

0.0000295

AC XY:

AN XY:

135794

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000894

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:

0.0000212

AC:

AN:

1461878

Hom.:

Cov.:

AF XY:

0.0000165

AC XY:

AN XY:

727240

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.000689

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000989

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152234

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74376

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:

0.0000441

Gnomad4 OTH

AF:

0.000478

Alfa

AF:

0.0000710

Hom.:

Bravo

AF:

0.0000416

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Oct 19, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Oct 20, 2023	The p.S232R variant (also known as c.696C>A), located in coding exon 2 of the BLM gene, results from a C to A substitution at nucleotide position 696. The serine at codon 232 is replaced by arginine, an amino acid with dissimilar properties. This alteration was identified in an individual diagnosed with pancreatic cancer at 55. A CHEK2 mutation (c.1283C>T) was also identified (Cox DM et al. Mol Genet Genomic Med, 2018 11;6:1236-1242). This amino acid position is not 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. -

Bloom syndrome

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 27, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Feb 18, 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.696C>A at the cDNA level, p.Ser232Arg (S232R) at the protein level, and results in the change of a Serine to an Arginine (AGC>AGA). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. BLM Ser232Arg was not observed at significant allele frequency in the NHLBI Exome Sequencing Project. This variant is a semi-conservative substitution in which a neutral polar amino acid is replaced with a positive polar one, altering a position that is only moderately conserved throughout evolution and is not located in a known functional domain (UniProt). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.097

BayesDel_addAF

Benign

-0.21

BayesDel_noAF

Benign

-0.54

CADD

Benign

0.040

DANN

Uncertain

0.99

DEOGEN2

Benign

0.095

T;.

Eigen

Benign

-1.2

Eigen_PC

Benign

-1.2

FATHMM_MKL

Benign

0.041

LIST_S2

Benign

0.61

T;T

M_CAP

Benign

0.020

MetaRNN

Benign

0.057

T;T

MetaSVM

Benign

-1.0

MutationAssessor

Uncertain

2.4

M;.

PrimateAI

Benign

0.26

PROVEAN

Benign

-2.0

N;N

REVEL

Benign

0.039

Sift

Benign

0.038

D;D

Sift4G

Benign

0.090

T;T

Polyphen

0.0020

B;.

Vest4

0.17

MutPred

0.21

Gain of sheet (P = 0.0266);Gain of sheet (P = 0.0266);

MVP

0.62

MPC

0.10

ClinPred

0.053

GERP RS

-4.0

Varity_R

0.12

gMVP

0.15

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