CHKB p.Arg194Gln

Variant names:

• chr22-50580661-C-T
• NM_005198.5:c.582-1G>A

Your query was ambiguous. Multiple possible variants found:

• chr22-50580661-C-T
• chr22-50580660-CC-TT

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_005198.5(CHKB):​c.582-1G>A variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHKB NM_005198.5 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 4.03
• Publications: 0 publications found

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:41998): (CHKB-CPT1B readthrough (NMD candidate)) The genes CHKB and CPT1B are adjacent on chromosome 22 and read-through transcripts are expressed that include exons from both loci. The read-through transcripts are candidates for nonsense-mediated mRNA decay (NMD) and are unlikely to express proteins. [provided by RefSeq, Jun 2009]

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.08080808 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005198.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHKB	NM_005198.5	MANE Select	c.582-1G>A		splice_acceptor intron	N/A	NP_005189.2
	CHKB-CPT1B	NR_027928.2		n.800-1G>A		splice_acceptor intron	N/A

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHKB	ENST00000406938.3	TSL:1 MANE Select	c.582-1G>A		splice_acceptor intron	N/A	ENSP00000384400.3	Q9Y259-1
	CHKB	ENST00000481673.5	TSL:1	n.1032-1G>A		splice_acceptor intron	N/A
	CHKB	ENST00000939160.1		c.663-1G>A		splice_acceptor intron	N/A	ENSP00000609219.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	35
DANN	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Uncertain	0.96	D
PhyloP100		4.0
Mutation Taster		=9/91	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.96		Position offset: -2
DS_AL_spliceai		1.0		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr22-51019090; COSMIC: COSV56417254; COSMIC: COSV56417254;