chr4-186257283-G-T

Variant names:

• chr4-186257283-G-T
• rs121964951
• NM_000892.5:c.1643G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2 PM5 PP3_Strong

The NM_000892.5(KLKB1):​c.1643G>T​(p.Cys548Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C548Y) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KLKB1 NM_000892.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.57
• Publications: 15 publications found

Genes affected

KLKB1 (HGNC:6371): (kallikrein B1) This gene encodes a glycoprotein that participates in the surface-dependent activation of blood coagulation, fibrinolysis, kinin generation and inflammation. The encoded preproprotein present in plasma as a non-covalent complex with high molecular weight kininogen undergoes proteolytic processing mediated by activated coagulation factor XII to generate a disulfide-linked, heterodimeric serine protease comprised of heavy and light chains. Certain mutations in this gene cause prekallikrein deficiency. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jan 2016]

KLKB1 Gene-Disease associations (from GenCC):

• inherited prekallikrein deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet, Labcorp Genetics (formerly Invitae)

ENSG00000290316 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr4-186257283-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 12035.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KLKB1	NM_000892.5	c.1643G>T	p.Cys548Phe	missense_variant	Exon 14 of 15	ENST00000264690.11	NP_000883.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KLKB1	ENST00000264690.11	c.1643G>T	p.Cys548Phe	missense_variant	Exon 14 of 15	1	NM_000892.5	ENSP00000264690.6
ENSG00000290316	ENST00000511608.5	c.1784G>T	p.Cys595Phe	missense_variant	Exon 14 of 15	5		ENSP00000426629.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	31
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
PhyloP100		8.6
PrimateAI	Uncertain	0.72	T
PROVEAN	Pathogenic	-9.3	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		0.94
MutPred		0.95		Loss of ubiquitination at K550 (P = 0.0901);
MVP		0.99
MPC		0.68
ClinPred		1.0	D
GERP RS		5.8
gMVP		0.99
Mutation Taster		=6/94	disease causing

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

Other links and lift over

dbSNP: rs121964951; hg19: chr4-187178437; COSMIC: COSV52995984;