chr17-44372199-A-G

Variant names:

• chr17-44372199-A-G
• NM_000419.5:c.*165T>C

Variant summary

Our verdict is Uncertain significance. Variant got 6 ACMG points: 6P and 0B. PM2_Supporting PP4_Strong PM3_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000419.5(ITGA2B):c.*165T>C 3'UTR variant was identified homozygous (PM3_supporting) in at least one patient (GT75 in PMID:25728920) who displayed mucocutaneous bleeding and impaired aggregation with all agonists except ristocetin, which is highly specific for Glanzmann thrombasthenia. Additionally, αIIbβ3 surface expression was reduced to <5%, as measured by flow cytometry (PP4_strong). This variant is absent from gnomAD v4.1 (PM2_Supporting). ACMG/AMP criteria applied, as specified by the ClinGen PD VCEP: PP4_strong, PM2_supporting, PM3_supporting. (VCEP specifications version 2.1). These criteria reach Likely Pathogenic however, to our knowledge, there is no known disease mechanism for 3'UTR variants in Glanzmann thrombasthenia. In the absence of additional cases or functional data the ClinGen PD VCEP classifies this variant as uncertain significance for autosomal recessive Glanzmann Thrombasthenia. LINK:https://erepo.genome.network/evrepo/ui/classification/CA915940530/MONDO:0100326/011

• Frequency: Genomes: not found (cov: 31)
• Consequence: ITGA2B NM_000419.5 3_prime_UTR
• Clinical Significance: Uncertain significance reviewed by expert panel U:1
• Conservation: PhyloP100: 4.07

Genes affected

ITGA2B (HGNC:6138): (integrin subunit alpha 2b) This gene encodes a member of the integrin alpha chain family of proteins. The encoded preproprotein is proteolytically processed to generate light and heavy chains that associate through disulfide linkages to form a subunit of the alpha-IIb/beta-3 integrin cell adhesion receptor. This receptor plays a crucial role in the blood coagulation system, by mediating platelet aggregation. Mutations in this gene are associated with platelet-type bleeding disorders, which are characterized by a failure of platelet aggregation, including Glanzmann thrombasthenia. [provided by RefSeq, Jan 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 6 ACMG points.

• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ITGA2B	NM_000419.5	c.*165T>C		3_prime_UTR_variant	Exon 30 of 30	ENST00000262407.6	NP_000410.2
ITGA2B	XM_011524749.2	c.*165T>C		3_prime_UTR_variant	Exon 29 of 29		XP_011523051.2
ITGA2B	XM_011524750.2	c.*165T>C		3_prime_UTR_variant	Exon 29 of 29		XP_011523052.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ITGA2B	ENST00000262407	c.*165T>C		3_prime_UTR_variant	Exon 30 of 30	1	NM_000419.5	ENSP00000262407.5
ITGA2B	ENST00000648408	c.*165T>C		3_prime_UTR_variant	Exon 25 of 25			ENSP00000498119.1
ITGA2B	ENST00000587295	c.*165T>C		3_prime_UTR_variant	Exon 3 of 3	3		ENSP00000467269.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 6

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: reviewed by expert panel

Submissions by phenotype

Glanzmann thrombasthenia Uncertain:1

Dec 17, 2024

ClinGen Platelet Disorders Variant Curation Expert Panel, ClinGen

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000419.5(ITGA2B):c.*165T>C 3'UTR variant was identified homozygous (PM3_supporting) in at least one patient (GT75 in PMID: 25728920) who displayed mucocutaneous bleeding and impaired aggregation with all agonists except ristocetin, which is highly specific for Glanzmann thrombasthenia. Additionally, αIIbβ3 surface expression was reduced to <5%, as measured by flow cytometry (PP4_strong). This variant is absent from gnomAD v4.1 (PM2_Supporting). ACMG/AMP criteria applied, as specified by the ClinGen PD VCEP: PP4_strong, PM2_supporting, PM3_supporting. (VCEP specifications version 2.1). These criteria reach Likely Pathogenic however, to our knowledge, there is no known disease mechanism for 3'UTR variants in Glanzmann thrombasthenia. In the absence of additional cases or functional data the ClinGen PD VCEP classifies this variant as uncertain significance for autosomal recessive Glanzmann Thrombasthenia. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.45
CADD	Benign	18
DANN	Benign	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: chr17-42449567;