17-4932668-G-T

Position:

• chr17-4932668-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_000173.7(GP1BA):​c.64G>T​(p.Val22Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: GP1BA NM_000173.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0840

Genes affected

GP1BA (HGNC:4439): (glycoprotein Ib platelet subunit alpha) Glycoprotein Ib (GP Ib) is a platelet surface membrane glycoprotein composed of a heterodimer, an alpha chain and a beta chain, that is linked by disulfide bonds. The Gp Ib functions as a receptor for von Willebrand factor (VWF). The complete receptor complex includes noncovalent association of the alpha and beta subunits with platelet glycoprotein IX and platelet glycoprotein V. The binding of the GP Ib-IX-V complex to VWF facilitates initial platelet adhesion to vascular subendothelium after vascular injury, and also initiates signaling events within the platelet that lead to enhanced platelet activation, thrombosis, and hemostasis. This gene encodes the alpha subunit. Mutations in this gene result in Bernard-Soulier syndromes and platelet-type von Willebrand disease. The coding region of this gene is known to contain a polymophic variable number tandem repeat (VNTR) domain that is associated with susceptibility to nonarteritic anterior ischemic optic neuropathy. [provided by RefSeq, Oct 2013]

CHRNE (HGNC:1966): (cholinergic receptor nicotinic epsilon subunit) Acetylcholine receptors at mature mammalian neuromuscular junctions are pentameric protein complexes composed of four subunits in the ratio of two alpha subunits to one beta, one epsilon, and one delta subunit. The acetylcholine receptor changes subunit composition shortly after birth when the epsilon subunit replaces the gamma subunit seen in embryonic receptors. Mutations in the epsilon subunit are associated with congenital myasthenic syndrome. [provided by RefSeq, Sep 2009]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a domain LRRNT (size 30) in uniprot entity GP1BA_HUMAN there are 4 pathogenic changes around while only 1 benign (80%) in NM_000173.7
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.28339118).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GP1BA	NM_000173.7	c.64G>T	p.Val22Phe	missense_variant	2/2	ENST00000329125.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GP1BA	ENST00000329125.6	c.64G>T	p.Val22Phe	missense_variant	2/2	1	NM_000173.7	P1
CHRNE	ENST00000649830.1	c.-888+1674C>A		intron_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 37

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 16, 2023

The c.64G>T (p.V22F) alteration is located in exon 2 (coding exon 1) of the GP1BA gene. This alteration results from a G to T substitution at nucleotide position 64, causing the valine (V) at amino acid position 22 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.48
CADD	Benign	16
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.75	D;T
Eigen	Benign	-0.52
Eigen_PC	Benign	-0.81
FATHMM_MKL	Benign	0.087	N
LIST_S2	Benign	0.57	T;T
M_CAP	Benign	0.064	D
MetaRNN	Benign	0.28	T;T
MetaSVM	Benign	-0.75	T
MutationAssessor	Benign	1.8	L;.
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-2.6	D;.
REVEL	Benign	0.19
Sift	Pathogenic	0.0	D;.
Sift4G	Benign	0.088	T;T
Vest4		0.14
MutPred		0.70		Gain of ubiquitination at K24 (P = 0.0804);Gain of ubiquitination at K24 (P = 0.0804);
MVP		0.60
MPC		0.61
ClinPred		0.94	D
GERP RS		-7.1
Varity_R		0.74
gMVP		0.57

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr17-4835963;