15-90760678-T-G

Variant names:

• chr15-90760678-T-G
• rs778967807
• NM_000057.4:c.1305T>G

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_Strong BP6_Very_Strong BP7

The NM_000057.4(BLM):​c.1305T>G​(p.Leu435Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000479 in 1,461,722 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 (★★). Synonymous variant affecting the same amino acid position (i.e. L435L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: BLM NM_000057.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:3
• Conservation: PhyloP100: -2.17
• 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

ACMG classification

Our verdict: Benign. The variant received -13 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.89).
• BP6: Variant 15-90760678-T-G is Benign according to our data. Variant chr15-90760678-T-G is described in ClinVar as Likely_benign. ClinVar VariationId is 818861.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-2.17 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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BLM	NM_000057.4	MANE Select	c.1305T>G	p.Leu435Leu	synonymous	Exon 7 of 22	NP_000048.1
	BLM	NM_001287246.2		c.1305T>G	p.Leu435Leu	synonymous	Exon 8 of 23	NP_001274175.1
	BLM	NM_001287247.2		c.1305T>G	p.Leu435Leu	synonymous	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.1305T>G	p.Leu435Leu	synonymous	Exon 7 of 22	ENSP00000347232.3
	BLM	ENST00000560509.5	TSL:1	c.1305T>G	p.Leu435Leu	synonymous	Exon 7 of 20	ENSP00000454158.1
	BLM	ENST00000559724.5	TSL:1	n.*229T>G		non_coding_transcript_exon	Exon 7 of 22	ENSP00000453359.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251206 AF XY: 0.00000737

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: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461722 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727182

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000630 AC: 7 AN: 1111874

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	2	Bloom syndrome (2)
-	-	1	Hereditary cancer-predisposing syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.89
CADD	Benign	0.041
DANN	Benign	0.43
PhyloP100		-2.2
Mutation Taster		=100/0	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs778967807; hg19: chr15-91303908;