NM_000057.4:c.3348C>T

Variant names:

• chr15-90798327-C-T
• rs372697241
• NM_000057.4:c.3348C>T

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 2P and 11B. PM2 BP4_Moderate BP6_Very_Strong BP7

The NM_000057.4(BLM):​c.3348C>T​(p.Asp1116Asp) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,612,752 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 Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BLM NM_000057.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:5
• Conservation: PhyloP100: 0.391
• Publications: 1 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: Benign. The variant received -9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.39).
• BP6: Variant 15-90798327-C-T is Benign according to our data. Variant chr15-90798327-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 413303.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=0.391 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000057.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BLM	NM_000057.4	MANE Select	c.3348C>T	p.Asp1116Asp	synonymous	Exon 17 of 22	NP_000048.1
	BLM	NM_001287246.2		c.3348C>T	p.Asp1116Asp	synonymous	Exon 18 of 23	NP_001274175.1
	BLM	NM_001287247.2		c.3348C>T	p.Asp1116Asp	synonymous	Exon 17 of 20	NP_001274176.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BLM	ENST00000355112.8	TSL:1 MANE Select	c.3348C>T	p.Asp1116Asp	synonymous	Exon 17 of 22	ENSP00000347232.3
	BLM	ENST00000560509.5	TSL:1	c.3348C>T	p.Asp1116Asp	synonymous	Exon 17 of 20	ENSP00000454158.1
	BLM	ENST00000559724.5	TSL:1	n.*2272C>T		non_coding_transcript_exon	Exon 17 of 22	ENSP00000453359.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152118 Hom.: 0 Cov.: 32

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1460634 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 726610

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33462

American (AMR) AF: 0.00 AC: 0 AN: 44660

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26106

East Asian (EAS) AF: 0.00 AC: 0 AN: 39546

South Asian (SAS) AF: 0.00 AC: 0 AN: 86108

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53194

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5754

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111462

Other (OTH) AF: 0.00 AC: 0 AN: 60342

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0136242), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152118 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74292

African (AFR) AF: 0.00 AC: 0 AN: 41428

American (AMR) AF: 0.00 AC: 0 AN: 15266

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10584

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68032

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000329 Hom.: 0

Bravo AF: 0.0000151

ClinVar

ClinVar submissions as Germline

Significance: Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	2	Bloom syndrome (2)
-	-	1	BLM-related disorder (1)
-	-	1	Hereditary cancer-predisposing syndrome (1)
-	-	1	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.39
CADD	Benign	9.3
DANN	Benign	0.51
PhyloP100		0.39

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs372697241; hg19: chr15-91341557;