1-197039216-G-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_Strong BS1_Supporting

The NM_001994.3(F13B):c.*162C>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000993 in 624,594 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0013 (1 hom., cov: 32)
  • Exomes 𝑓: 0.00090 (1 hom.)
• Consequence: F13B NM_001994.3 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.346

Genes affected

F13B (HGNC:3534): (coagulation factor XIII B chain) This gene encodes coagulation factor XIII B subunit. Coagulation factor XIII is the last zymogen to become activated in the blood coagulation cascade. Plasma factor XIII is a heterotetramer composed of 2 A subunits and 2 B subunits. The A subunits have catalytic function, and the B subunits do not have enzymatic activity and may serve as a plasma carrier molecules. Platelet factor XIII is comprised only of 2 A subunits, which are identical to those of plasma origin. Upon activation by the cleavage of the activation peptide by thrombin and in the presence of calcium ion, the plasma factor XIII dissociates its B subunits and yields the same active enzyme, factor XIIIa, as platelet factor XIII. This enzyme acts as a transglutaminase to catalyze the formation of gamma-glutamyl-epsilon-lysine crosslinking between fibrin molecules, thus stabilizing the fibrin clot. Factor XIII deficiency is classified into two categories: type I deficiency, characterized by the lack of both the A and B subunits; and type II deficiency, characterized by the lack of the A subunit alone. These defects can result in a lifelong bleeding tendency, defective wound healing, and habitual abortion. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.91).
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00127 (193/152046) while in subpopulation AFR AF= 0.00244 (101/41476). AF 95% confidence interval is 0.00205. There are 1 homozygotes in gnomad4. There are 85 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
F13B	NM_001994.3	c.*162C>A		3_prime_UTR_variant	12/12	ENST00000367412.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
F13B	ENST00000367412.2	c.*162C>A		3_prime_UTR_variant	12/12	1	NM_001994.3	P1
F13B	ENST00000649282.1	c.*162C>A		3_prime_UTR_variant	5/5

Frequencies

GnomAD3 genomes AF: 0.00127 AC: 193 AN: 151928 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.00244

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000393

Gnomad ASJ AF: 0.0156

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000412

Gnomad OTH AF: 0.00192

GnomAD4 exome AF: 0.000904 AC: 427 AN: 472548 Hom.: 1 Cov.: 5 AF XY: 0.000873 AC XY: 222 AN XY: 254408

Gnomad4 AFR exome AF: 0.00211

Gnomad4 AMR exome AF: 0.000417

Gnomad4 ASJ exome AF: 0.0158

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000450

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000371

Gnomad4 OTH exome AF: 0.00214

GnomAD4 genome AF: 0.00127 AC: 193 AN: 152046 Hom.: 1 Cov.: 32 AF XY: 0.00114 AC XY: 85 AN XY: 74304

Gnomad4 AFR AF: 0.00244

Gnomad4 AMR AF: 0.000393

Gnomad4 ASJ AF: 0.0156

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000412

Gnomad4 OTH AF: 0.00190

Bravo AF: 0.00139

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Factor XIII, b subunit, deficiency of Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.91
Cadd	Benign	0.39
Dann	Benign	0.24

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

LitVar

Other links and lift over

dbSNP: rs180977741; hg19: chr1-197008346;