15-90749472-C-T

Variant names:

• chr15-90749472-C-T
• rs199927688
• NM_000057.4:c.204C>T

Variant summary

Our verdict is Benign. The variant received -16 ACMG points: 0P and 16B. BP4_Strong BP6_Very_Strong BS1

The NM_001287248.2(BLM):​c.-1088C>T variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000107 in 1,613,030 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.000079 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (1 hom.)
• Consequence: BLM NM_001287248.2 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: -2.02
• 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: Orphanet, Labcorp Genetics (formerly Invitae), G2P, Myriad Women’s Health, Genomics England PanelApp, ClinGen, Laboratory for Molecular Medicine
• osteosarcoma

  Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
• colorectal cancer

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• 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 -16 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).
• BP6: Variant 15-90749472-C-T is Benign according to our data. Variant chr15-90749472-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 524828.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.0000789 (12/152176) while in subpopulation SAS AF = 0.00228 (11/4824). AF 95% confidence interval is 0.00128. There are 0 homozygotes in GnomAd4. There are 8 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001287248.2. 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.204C>T	p.Thr68Thr	synonymous	Exon 3 of 22	NP_000048.1	P54132
	BLM	NM_001287248.2		c.-1088C>T		5_prime_UTR_premature_start_codon_gain	Exon 3 of 22	NP_001274177.1
	BLM	NM_001287246.2		c.204C>T	p.Thr68Thr	synonymous	Exon 4 of 23	NP_001274175.1	P54132

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BLM	ENST00000355112.8	TSL:1 MANE Select	c.204C>T	p.Thr68Thr	synonymous	Exon 3 of 22	ENSP00000347232.3	P54132
	BLM	ENST00000560509.5	TSL:1	c.204C>T	p.Thr68Thr	synonymous	Exon 3 of 20	ENSP00000454158.1	H0YNU5
	BLM	ENST00000559724.5	TSL:1	n.204C>T		non_coding_transcript_exon	Exon 3 of 22	ENSP00000453359.1	H0YLV8

Frequencies

GnomAD3 genomes AF: 0.0000789 AC: 12 AN: 152058 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: 0.00228

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000247 AC: 62 AN: 250996 AF XY: 0.000294

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: 0.0000176

Gnomad OTH exome AF: 0.000490

GnomAD4 exome AF: 0.000110 AC: 161 AN: 1460854 Hom.: 1 Cov.: 31 AF XY: 0.000164 AC XY: 119 AN XY: 726808

African (AFR) AF: 0.00 AC: 0 AN: 33464

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00160 AC: 138 AN: 86212

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.000173 AC: 1 AN: 5764

European-Non Finnish (NFE) AF: 0.00000720 AC: 8 AN: 1111108

Other (OTH) AF: 0.000232 AC: 14 AN: 60368

GnomAD4 genome AF: 0.0000789 AC: 12 AN: 152176 Hom.: 0 Cov.: 32 AF XY: 0.000108 AC XY: 8 AN XY: 74412

African (AFR) AF: 0.00 AC: 0 AN: 41520

American (AMR) AF: 0.00 AC: 0 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5184

South Asian (SAS) AF: 0.00228 AC: 11 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10576

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 67998

Other (OTH) AF: 0.00 AC: 0 AN: 2112

Alfa AF: 0.0000434 Hom.: 0

Bravo AF: 0.0000113

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

ClinVar submissions

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

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

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	0.30
DANN	Benign	0.26
PhyloP100		-2.0
Mutation Taster		=99/1	polymorphism

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: rs199927688; hg19: chr15-91292702;