22-50580198-A-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_005198.5(CHKB):c.810T>A(p.Tyr270*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000204 in 1,613,748 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. Y270Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

CHKB
NM_005198.5 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, single submitter P:3

Conservation

PhyloP100: -0.0180

Publications

3 publications found

Variant links:

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 links:

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]

CHKB-CPT1B links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 22-50580198-A-T is Pathogenic according to our data. Variant chr22-50580198-A-T is described in ClinVar as Pathogenic. ClinVar VariationId is 30952.Status of the report is criteria_provided_single_submitter, 1 stars.

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHKB	NM_005198.5	MANE Select	c.810T>A	p.Tyr270*	stop_gained	Exon 7 of 11	NP_005189.2
	CHKB-CPT1B	NR_027928.2		n.1028T>A		non_coding_transcript_exon	Exon 7 of 30

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CHKB	ENST00000406938.3	TSL:1 MANE Select	c.810T>A	p.Tyr270*	stop_gained	Exon 7 of 11	ENSP00000384400.3
CHKB	ENST00000481673.5	TSL:1	n.1260T>A		non_coding_transcript_exon	Exon 6 of 10
CHKB	ENST00000464225.5	TSL:2	n.56T>A		non_coding_transcript_exon	Exon 1 of 5

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152202

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000798

AC:

AN:

250764

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000177

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000205

AC:

AN:

1461546

Hom.:

Cov.:

AF XY:

0.0000289

AC XY:

AN XY:

727046

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86242

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53246

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5752

European-Non Finnish (NFE)

AF:

0.0000252

AC:

AN:

1111892

Other (OTH)

AF:

0.0000166

AC:

AN:

60374

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152202

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74362

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41444

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.542

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000359

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Megaconial type congenital muscular dystrophy

Pathogenic:2

Jan 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Tyr270*) in the CHKB gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CHKB are known to be pathogenic (PMID: 21665002). This variant is present in population databases (rs750764003, gnomAD 0.002%). This premature translational stop signal has been observed in individuals with congenital muscular dystrophy (PMID: 21665002, 26006750). ClinVar contains an entry for this variant (Variation ID: 30952). For these reasons, this variant has been classified as Pathogenic.

Nov 01, 2014

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

CHKB-related disorder

Pathogenic:1

May 30, 2024

PreventionGenetics, part of Exact Sciences

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

The CHKB c.810T>A variant is predicted to result in premature protein termination (p.Tyr270*). This variant was reported in individuals with autosomal recessive congenital muscular dystrophy and mitochondrial enlargement (Mitsuhashi et al. 2011. PubMed ID: 21665002; Castro-Gago et al. 2014. PubMed ID: 24997086). This variant is reported in 0.0023% of alleles in individuals of European (Non-Finnish) descent in gnomAD. Nonsense variants in CHKB are expected to be pathogenic. This variant is interpreted as pathogenic.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.61

BayesDel_noAF

Pathogenic

0.56

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Benign

0.095

Eigen_PC

Benign

-0.13

FATHMM_MKL

Uncertain

0.83

PhyloP100

-0.018

Vest4

0.93

GERP RS

-3.1

Mutation Taster

=2/198

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over