15-90794338-A-T

Variant names:

• chr15-90794338-A-T
• rs367543032
• NM_000057.4:c.3191A>T

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_000057.4(BLM):​c.3191A>T​(p.Asp1064Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D1064G) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BLM NM_000057.4 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.07
• Publications: 3 publications found

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

ENSG00000300894 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959
• PP5: Variant 15-90794338-A-T is Pathogenic according to our data. Variant chr15-90794338-A-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3224403.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BLM	NM_000057.4	c.3191A>T	p.Asp1064Val	missense_variant	Exon 16 of 22	ENST00000355112.8	NP_000048.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BLM	ENST00000355112.8	c.3191A>T	p.Asp1064Val	missense_variant	Exon 16 of 22	1	NM_000057.4	ENSP00000347232.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Bloom syndrome Pathogenic:1

Mar 23, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Dec 20, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.D1064V variant (also known as c.3191A>T), located in coding exon 15 of the BLM gene, results from an A to T substitution at nucleotide position 3191. The aspartic acid at codon 1064 is replaced by valine, an amino acid with highly dissimilar properties. This variant has been identified likely in trans with a BLM pathogenic variant in an individual diagnosed with Bloom syndrome (German J et al. Hum Mutat, 2007 Aug;28:743-53). Functional studies suggest that this variant causes sensitivity to DNA damaging agents (Mirzaei H et al. Proc Natl Acad Sci U S A, 2012 Nov;109:19357-62). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	33
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.70	D;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D;D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Pathogenic	0.80	D
MutationAssessor	Pathogenic	4.2	H;.
PhyloP100		9.1
PrimateAI	Uncertain	0.66	T
PROVEAN	Pathogenic	-8.6	D;D
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.95
MutPred		0.83		Loss of disorder (P = 0.0295);Loss of disorder (P = 0.0295);
MVP		0.96
MPC		0.57
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.97
gMVP		0.82
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.30		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.30		Position offset: -28

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs367543032; hg19: chr15-91337568;