rs140382474

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_000057.4(BLM):​c.191A>C​(p.Asp64Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,760 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 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. D64V) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

BLM
NM_000057.4 missense

Scores

8
11

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 2.43

Publications

11 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: Myriad Women’s Health, Labcorp Genetics (formerly Invitae), G2P, Laboratory for Molecular Medicine, Orphanet, Genomics England PanelApp, ClinGen
  • osteosarcoma
    Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
  • breast cancer
    Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
  • hereditary nonpolyposis colon cancer
    Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.25040653).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
BLMNM_000057.4 linkc.191A>C p.Asp64Ala missense_variant Exon 3 of 22 ENST00000355112.8 NP_000048.1 P54132

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
BLMENST00000355112.8 linkc.191A>C p.Asp64Ala missense_variant Exon 3 of 22 1 NM_000057.4 ENSP00000347232.3 P54132

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD2 exomes
AF:
0.00000399
AC:
1
AN:
250804
AF XY:
0.00
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:
0.00000882
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
6.85e-7
AC:
1
AN:
1459760
Hom.:
0
Cov.:
31
AF XY:
0.00000138
AC XY:
1
AN XY:
726368
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33434
American (AMR)
AF:
0.00
AC:
0
AN:
44718
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26118
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39680
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86216
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53412
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
9.01e-7
AC:
1
AN:
1110098
Other (OTH)
AF:
0.00
AC:
0
AN:
60318
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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
Cov.:
32
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000378

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Bloom syndrome Uncertain:1
Sep 04, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with alanine, which is neutral and non-polar, at codon 64 of the BLM protein (p.Asp64Ala). This variant is present in population databases (no rsID available, gnomAD 0.0009%). 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: 287232). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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
Apr 25, 2016
Eurofins Ntd Llc (ga)
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1
Feb 20, 2025
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.D64A variant (also known as c.191A>C), located in coding exon 2 of the BLM gene, results from an A to C substitution at nucleotide position 191. The aspartic acid at codon 64 is replaced by alanine, an amino acid with dissimilar properties. 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.16
BayesDel_addAF
Uncertain
0.039
T
BayesDel_noAF
Benign
-0.18
CADD
Benign
22
DANN
Uncertain
0.99
DEOGEN2
Benign
0.24
T;.
Eigen
Uncertain
0.19
Eigen_PC
Benign
0.18
FATHMM_MKL
Uncertain
0.83
D
LIST_S2
Benign
0.70
T;T
M_CAP
Benign
0.065
D
MetaRNN
Benign
0.25
T;T
MetaSVM
Benign
-0.63
T
MutationAssessor
Uncertain
2.4
M;.
PhyloP100
2.4
PrimateAI
Benign
0.38
T
PROVEAN
Uncertain
-2.4
N;D
REVEL
Benign
0.20
Sift
Uncertain
0.0050
D;D
Sift4G
Uncertain
0.030
D;D
Polyphen
0.92
P;.
Vest4
0.32
MutPred
0.21
Loss of stability (P = 0.0465);Loss of stability (P = 0.0465);
MVP
0.84
MPC
0.43
ClinPred
0.82
D
GERP RS
3.5
Varity_R
0.16
gMVP
0.22

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

Other links and lift over

dbSNP: rs140382474; hg19: chr15-91292689; API