rs777886082

Variant names:

• chr15-90760638-GTCT-G
• rs777886082
• NM_000057.4:c.1270_1272delCTT

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PM4_Supporting

The NM_000057.4(BLM):​c.1270_1272delCTT​(p.Leu424del) variant causes a conservative inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,612,426 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. L424L) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000096 (0 hom.)
• Consequence: BLM NM_000057.4 conservative_inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 0.467
• Publications: 0 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

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM4: Nonframeshift variant in NON repetitive region in NM_000057.4. Strenght limited to Supporting due to length of the change: 1aa.

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BLM	NM_000057.4	MANE Select	c.1270_1272delCTT	p.Leu424del	conservative_inframe_deletion	Exon 7 of 22	NP_000048.1
	BLM	NM_001287246.2		c.1270_1272delCTT	p.Leu424del	conservative_inframe_deletion	Exon 8 of 23	NP_001274175.1
	BLM	NM_001287247.2		c.1270_1272delCTT	p.Leu424del	conservative_inframe_deletion	Exon 7 of 20	NP_001274176.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BLM	ENST00000355112.8	TSL:1 MANE Select	c.1270_1272delCTT	p.Leu424del	conservative_inframe_deletion	Exon 7 of 22	ENSP00000347232.3
	BLM	ENST00000560509.5	TSL:1	c.1270_1272delCTT	p.Leu424del	conservative_inframe_deletion	Exon 7 of 20	ENSP00000454158.1
	BLM	ENST00000559724.5	TSL:1	n.*194_*196delCTT		non_coding_transcript_exon	Exon 7 of 22	ENSP00000453359.1

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 152188 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000262

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: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250558 AF XY: 0.00

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: 0.00000959 AC: 14 AN: 1460238 Hom.: 0 AF XY: 0.00000826 AC XY: 6 AN XY: 726150

African (AFR) AF: 0.00 AC: 0 AN: 33444

American (AMR) AF: 0.0000224 AC: 1 AN: 44622

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26116

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39658

South Asian (SAS) AF: 0.00 AC: 0 AN: 86102

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53320

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000990 AC: 11 AN: 1110904

Other (OTH) AF: 0.0000166 AC: 1 AN: 60310

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152188 Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3 AN XY: 74356

African (AFR) AF: 0.0000241 AC: 1 AN: 41448

American (AMR) AF: 0.000262 AC: 4 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5202

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68006

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.000125

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	2	-	Bloom syndrome (2)
-	2	-	not provided (2)
-	1	-	Hereditary cancer-predisposing syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.47
Mutation Taster		=91/9	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs777886082; hg19: chr15-91303868;