chr17-4932666-A-C

Position:

• chr17-4932666-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000173.7(GP1BA):​c.62A>C​(p.Glu21Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,662 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: GP1BA NM_000173.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.02

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GP1BA	NM_000173.7	c.62A>C	p.Glu21Ala	missense_variant	2/2	ENST00000329125.6	NP_000164.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GP1BA	ENST00000329125.6	c.62A>C	p.Glu21Ala	missense_variant	2/2	1	NM_000173.7	ENSP00000329380.5
CHRNE	ENST00000649830.1	c.-888+1676T>G		intron_variant				ENSP00000496907.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461662 Hom.: 0 Cov.: 37 AF XY: 0.00000138 AC XY: 1 AN XY: 727126

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jun 07, 2024

Variant summary: GP1BA c.62A>C (p.Glu21Ala) results in a non-conservative amino acid change located in the Leucine-rich repeat N-terminal domain (IPR000372) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 249232 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.62A>C in individuals affected with Bernard-Soulier Syndrome, Type A2, Autosomal Dominant and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Uncertain	0.023	T
BayesDel_noAF	Benign	-0.21
CADD	Benign	22
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.84	D;T
Eigen	Benign	-0.34
Eigen_PC	Benign	-0.43
FATHMM_MKL	Benign	0.68	D
LIST_S2	Benign	0.59	T;T
M_CAP	Pathogenic	0.51	D
MetaRNN	Uncertain	0.43	T;T
MetaSVM	Uncertain	0.34	D
MutationAssessor	Benign	1.5	L;.
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-3.4	D;.
REVEL	Uncertain	0.34
Sift	Uncertain	0.0020	D;.
Sift4G	Benign	0.10	T;T
Vest4		0.21
MutPred		0.51		Gain of ubiquitination at K24 (P = 0.046);Gain of ubiquitination at K24 (P = 0.046);
MVP		0.91
MPC		0.53
ClinPred		0.75	D
GERP RS		0.61
Varity_R		0.54
gMVP		0.55

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.080		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: chr17-4835961;