chr15-90751943-TTAGGTAAAC-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PVS1PM2PP5

The NM_000057.4(BLM):​c.959+1_959+9del variant causes a splice donor, splice donor 5th base, coding sequence, intron change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000027 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

BLM
NM_000057.4 splice_donor, splice_donor_5th_base, coding_sequence, intron

Scores

Not classified

Clinical Significance

Likely pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 5.17
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]

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 11 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 15-90751943-TTAGGTAAAC-T is Pathogenic according to our data. Variant chr15-90751943-TTAGGTAAAC-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 556630.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=3, Uncertain_significance=1}.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
BLMNM_000057.4 linkuse as main transcriptc.959+1_959+9del splice_donor_variant, splice_donor_5th_base_variant, coding_sequence_variant, intron_variant 4/22 ENST00000355112.8 NP_000048.1

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
BLMENST00000355112.8 linkuse as main transcriptc.959+1_959+9del splice_donor_variant, splice_donor_5th_base_variant, coding_sequence_variant, intron_variant 4/221 NM_000057.4 ENSP00000347232 P2

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD3 exomes
AF:
0.00000797
AC:
2
AN:
250890
Hom.:
0
AF XY:
0.00
AC XY:
0
AN XY:
135652
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:
0.0000654
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
Data not reliable, filtered out with message: AS_VQSR
AF:
0.00000275
AC:
4
AN:
1456014
Hom.:
0
AF XY:
0.00000276
AC XY:
2
AN XY:
724618
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:
0.0000465
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
Cov.:
32
Asia WGS
AF:
0.000289
AC:
1
AN:
3476

ClinVar

Significance: Likely pathogenic
Submissions summary: Pathogenic:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Bloom syndrome Pathogenic:4
Likely pathogenic, no assertion criteria providedclinical testingNatera, Inc.Jun 15, 2021- -
Likely pathogenic, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpApr 15, 2022In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 556630). This variant has not been reported in the literature in individuals affected with BLM-related conditions. This variant is present in population databases (rs765061205, gnomAD 0.007%). This sequence change affects a splice site in intron 4 of the BLM gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in BLM are known to be pathogenic (PMID: 17407155). -
Likely pathogenic, criteria provided, single submitterclinical testingCounsylFeb 13, 2018- -
Likely pathogenic, criteria provided, single submitterclinical testingBaylor GeneticsMar 01, 2024- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction

Splicing

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.

Other links and lift over

dbSNP: rs765061205; hg19: chr15-91295173; API