rs893352310

chr15-90798266-G-Achr15-90798266-G-Cchr15-90798266-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000057.4(BLM):c.3287G>A(p.Gly1096Glu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G1096R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BLM NM_000057.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.60

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.29517636).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BLM	NM_000057.4	c.3287G>A	p.Gly1096Glu	missense_variant	17/22	ENST00000355112.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BLM	ENST00000355112.8	c.3287G>A	p.Gly1096Glu	missense_variant	17/22	1	NM_000057.4	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bloom syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 07, 2021

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The glutamic acid amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with BLM-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with glutamic acid at codon 1096 of the BLM protein (p.Gly1096Glu). The glycine residue is moderately conserved and there is a moderate physicochemical difference between glycine and glutamic acid. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.092	T
BayesDel_noAF	Benign	-0.37
Cadd	Benign	22
Dann	Uncertain	0.99
DEOGEN2	Benign	0.36	T;.
Eigen	Uncertain	0.41
Eigen_PC	Uncertain	0.34
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.67	T;T
M_CAP	Benign	0.045	D
MetaRNN	Benign	0.30	T;T
MetaSVM	Benign	-0.69	T
MutationAssessor	Uncertain	2.8	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.44	T
PROVEAN	Uncertain	-3.8	D;D
REVEL	Benign	0.27
Sift	Uncertain	0.0050	D;D
Sift4G	Uncertain	0.0090	D;D
Polyphen		0.94	P;.
Vest4		0.32
MutPred		0.48		Loss of MoRF binding (P = 0.0329);Loss of MoRF binding (P = 0.0329);
MVP		0.89
MPC		0.15
ClinPred		0.96	D
GERP RS		4.4
Varity_R		0.35
gMVP		0.82

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr15-91341496;