22-19723558-C-T

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000407.5(GP1BB):c.-12C>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 0.000027 in 1,593,728 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000028 ( 0 hom. )

Consequence

GP1BB
NM_000407.5 5_prime_UTR_premature_start_codon_gain

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -1.67

Variant links:

Genes affected

GP1BB (HGNC:4440): (glycoprotein Ib platelet subunit beta) Platelet glycoprotein Ib (GPIb) is a heterodimeric transmembrane protein consisting of a disulfide-linked 140 kD alpha chain and 22 kD beta chain. It is part of the GPIb-V-IX system that constitutes the receptor for von Willebrand factor (VWF), and mediates platelet adhesion in the arterial circulation. GPIb alpha chain provides the VWF binding site, and GPIb beta contributes to surface expression of the receptor and participates in transmembrane signaling through phosphorylation of its intracellular domain. Mutations in the GPIb beta subunit have been associated with Bernard-Soulier syndrome, velocardiofacial syndrome and giant platelet disorder. The 206 amino acid precursor of GPIb beta is synthesized from a 1.0 kb mRNA expressed in plateletes and megakaryocytes. A 411 amino acid protein arising from a longer, unspliced transcript in endothelial cells has been described; however, the authenticity of this product has been questioned. Yet another less abundant GPIb beta mRNA species of 3.5 kb, expressed in nonhematopoietic tissues such as endothelium, brain and heart, was shown to result from inefficient usage of a non-consensus polyA signal in the neighboring upstream gene (SEPT5, septin 5). In the absence of polyadenylation from its own imperfect site, the SEPT5 gene produces read-through transcripts that use the consensus polyA signal of this gene. [provided by RefSeq, Dec 2010]

GP1BB links:

ENSG00000284874 (HGNC:):

ENSG00000284874 links:

SEPTIN5 (HGNC:9164): (septin 5) This gene is a member of the septin gene family of nucleotide binding proteins, originally described in yeast as cell division cycle regulatory proteins. Septins are highly conserved in yeast, Drosophila, and mouse and appear to regulate cytoskeletal organization. Disruption of septin function disturbs cytokinesis and results in large multinucleate or polyploid cells. This gene is mapped to 22q11, the region frequently deleted in DiGeorge and velocardiofacial syndromes. A translocation involving the MLL gene and this gene has also been reported in patients with acute myeloid leukemia. Alternative splicing results in multiple transcript variants. The presence of a non-consensus polyA signal (AACAAT) in this gene also results in read-through transcription into the downstream neighboring gene (GP1BB; platelet glycoprotein Ib), whereby larger, non-coding transcripts are produced. [provided by RefSeq, Dec 2010]

SEPTIN5 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.71).

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
GP1BB	NM_000407.5 link	c.-12C>T	5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 2	ENST00000366425.4	NP_000398.1	P13224-1
GP1BB	NM_000407.5 link	c.-12C>T	5_prime_UTR_variant	Exon 1 of 2	ENST00000366425.4	NP_000398.1	P13224-1
SEPTIN5	NM_002688.6 link	c.*1074C>T	downstream_gene_variant		ENST00000455784.7	NP_002679.2	Q99719-1X5DNA9

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	MANE	Protein	UniProt
GP1BB	ENST00000366425 link	c.-12C>T	5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 2	1	NM_000407.5	ENSP00000383382.2	P13224-1
GP1BB	ENST00000366425 link	c.-12C>T	5_prime_UTR_variant	Exon 1 of 2	1	NM_000407.5	ENSP00000383382.2	P13224-1
ENSG00000284874	ENST00000455843.5 link	n.*1074C>T	non_coding_transcript_exon_variant	Exon 11 of 12	1		ENSP00000391731.1	G3XAH0
ENSG00000284874	ENST00000455843.5 link	n.*1074C>T	3_prime_UTR_variant	Exon 11 of 12	1		ENSP00000391731.1	G3XAH0
SEPTIN5	ENST00000455784.7 link	c.*1074C>T	downstream_gene_variant		1	NM_002688.6	ENSP00000391311.2	Q99719-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152208

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.000576

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000597

AC:

AN:

217688

Hom.:

AF XY:

0.0000584

AC XY:

AN XY:

119888

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00117

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000102

Gnomad OTH exome

AF:

0.000181

GnomAD4 exome

AF:

0.0000284

AC:

AN:

1441520

Hom.:

Cov.:

AF XY:

0.0000279

AC XY:

AN XY:

716554

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.000736

Gnomad4 EAS exome

AF:

0.0000255

Gnomad4 SAS exome

AF:

0.0000119

Gnomad4 FIN exome

AF:

0.0000235

Gnomad4 NFE exome

AF:

0.00000994

Gnomad4 OTH exome

AF:

0.000134

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152208

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74364

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.000576

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000302

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

May 17, 2024

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: GP1BB c.-12C>T is located in the untranslated mRNA region upstream of the initiation codon. The variant allele was found at a frequency of 6e-05 in 217688 control chromosomes (gnomAD). To our knowledge, no occurrence of c.-12C>T in individuals affected with Bernard Soulier Syndrome 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

BayesDel_noAF

Benign

-0.71

CADD

Benign

9.1

DANN

Benign

0.87

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over