22-50580080-C-A

Position:

• chr22-50580080-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_005198.5(CHKB):​c.821G>T​(p.Gly274Val) variant causes a missense, splice region 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. 1/1 splice prediction tools predict no significant impact on normal splicing. 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. G274D) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHKB NM_005198.5 missense, splice_region
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.70

Genes affected

CHKB (HGNC:1938): (choline kinase beta) Choline kinase (CK) and ethanolamine kinase (EK) catalyze the phosphorylation of choline/ethanolamine to phosphocholine/phosphoethanolamine. This is the first enzyme in the biosynthesis of phosphatidylcholine/phosphatidylethanolamine in all animal cells. The highly purified CKs from mammalian sources and their recombinant gene products have been shown to have EK activity also, indicating that both activities reside on the same protein. The choline kinase-like protein encoded by CHKL belongs to the choline/ethanolamine kinase family; however, its exact function is not known. Read-through transcripts are expressed from this locus that include exons from the downstream CPT1B locus. [provided by RefSeq, Jun 2009]

CHKB-CPT1B (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.952

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHKB	NM_005198.5	c.821G>T	p.Gly274Val	missense_variant, splice_region_variant	8/11	ENST00000406938.3
CHKB-CPT1B	NR_027928.2	n.1039G>T		splice_region_variant, non_coding_transcript_exon_variant	8/30

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHKB	ENST00000406938.3	c.821G>T	p.Gly274Val	missense_variant, splice_region_variant	8/11	1	NM_005198.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	T
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D
M_CAP	Uncertain	0.15	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Uncertain	0.13	D
MutationAssessor	Pathogenic	3.2	M
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.80	T
PROVEAN	Pathogenic	-7.7	D
REVEL	Pathogenic	0.73
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.81		Loss of stability (P = 0.0525);
MVP		0.95
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.96
gMVP		0.93

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: rs1555894469; hg19: chr22-51018509;