rs780379121

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000057.4(BLM):c.3028del(p.Asp1010MetfsTer24) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000563 in 1,599,500 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

BLM
NM_000057.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:10

Conservation

PhyloP100: 9.33

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 Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 15-90794174-AG-A is Pathogenic according to our data. Variant chr15-90794174-AG-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 189048.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BLM	NM_000057.4 linkuse as main transcript	c.3028del	p.Asp1010MetfsTer24	frameshift_variant	16/22	ENST00000355112.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BLM	ENST00000355112.8 linkuse as main transcript	c.3028del	p.Asp1010MetfsTer24	frameshift_variant	16/22	1	NM_000057.4	P2

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152158

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:

0.00

GnomAD3 exomes

AF:

0.0000121

AC:

AN:

248358

Hom.:

AF XY:

0.00000745

AC XY:

AN XY:

134304

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:

0.0000266

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000415

AC:

AN:

1447342

Hom.:

Cov.:

AF XY:

0.00000555

AC XY:

AN XY:

720406

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:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000544

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152158

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74338

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:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Bloom syndrome

Pathogenic:7

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 22, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jun 17, 2019	Variant summary: BLM c.3028delG (p.Asp1010MetfsX24) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 1.2e-05 in 248358 control chromosomes (gnomAD). c.3028delG has been reported in the literature in a homozygous and compound heterozygote individuals affected with Bloom Syndrome (German_2007). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two ClinVar submissions from clinical diagnostic laboratories (evaluation after 2014) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Dec 23, 2021	- -
Pathogenic, no assertion criteria provided	clinical testing	Zotz-Klimas Genetics Lab, MVZ Zotz Klimas	Nov 24, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 22, 2023	This sequence change creates a premature translational stop signal (p.Asp1010Metfs*24) in the BLM gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BLM are known to be pathogenic (PMID: 17407155). This variant is present in population databases (rs780379121, gnomAD 0.004%). This premature translational stop signal has been observed in individual(s) with Bloom syndrome (PMID: 17407155). ClinVar contains an entry for this variant (Variation ID: 189048). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	literature only	Counsyl	Nov 06, 2014	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Mar 16, 2017	- -

not provided

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden	Nov 03, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	May 13, 2021	DNA sequence analysis of the BLM gene demonstrated a single base pair deletion in exon 16, c.3028del. This sequence change results in an amino acid frameshift and creates a premature stop codon 24 amino acids downstream of the change, p.Asp1010Metfs*24. This sequence change is predicted to result in an abnormal transcript, which may be degraded, or may lead to the production of a truncated BLM protein with potentially abnormal function. This sequence change has been previously described in the homozygous and compound heterozygous states in three individuals with Bloom syndrome (PMID: 17407155). This sequence change has been described in four non-Finnish European individuals in the gnomAD population database (rs780379121). Collectively these evidences suggest that, the c.3028del change is likely pathogenic, however functional studies have not been performed to prove this conclusively. -

Hereditary cancer-predisposing syndrome

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 08, 2024

The c.3028delG pathogenic mutation, located in coding exon 15 of the BLM gene, results from a deletion of one nucleotide at nucleotide position 3028, causing a translational frameshift with a predicted alternate stop codon (p.D1010Mfs*24). This alteration has been reported in three individuals with Bloom syndrome, one of whom was homozygous for c.3028delG (German J et al. Hum. Mutat. 2007 Aug;28:743-53). This alteration was also identified in a cohort of metastatic prostate cancer patients (Ledet EM et al. Prostate. 2020 02;80:235-237). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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