rs757983603

chr22-50579821-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_005198.5(CHKB):c.937A>G(p.Ile313Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000105 in 1,613,598 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000096 (0 hom.)
• Consequence: CHKB NM_005198.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.99

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.22553101).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHKB	NM_005198.5	c.937A>G	p.Ile313Val	missense_variant	9/11	ENST00000406938.3
CHKB-CPT1B	NR_027928.2	n.1155A>G		non_coding_transcript_exon_variant	9/30

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHKB	ENST00000406938.3	c.937A>G	p.Ile313Val	missense_variant	9/11	1	NM_005198.5	P1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152118 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.000478

GnomAD3 exomes AF: 0.00000402 AC: 1 AN: 248802 Hom.: 0 AF XY: 0.00000742 AC XY: 1 AN XY: 134726

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000898

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000958 AC: 14 AN: 1461480 Hom.: 0 Cov.: 31 AF XY: 0.0000110 AC XY: 8 AN XY: 727054

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000126

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152118 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74290

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.000478

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Megaconial type congenital muscular dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 04, 2018

This sequence change replaces isoleucine with valine at codon 313 of the CHKB protein (p.Ile313Val). The isoleucine residue is moderately conserved and there is a small physicochemical difference between isoleucine and valine. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant is present in population databases (rs757983603, ExAC 0.001%). This variant has not been reported in the literature in individuals with CHKB-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.46
Cadd	Benign	22
Dann	Uncertain	0.98
DEOGEN2	Benign	0.14	T
Eigen	Benign	-0.23
Eigen_PC	Benign	-0.081
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.93	D
M_CAP	Benign	0.011	T
MetaRNN	Benign	0.23	T
MetaSVM	Benign	-0.95	T
MutationAssessor	Benign	1.8	L
MutationTaster	Benign	0.98	D
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-0.56	N
REVEL	Benign	0.067
Sift	Benign	0.26	T
Sift4G	Benign	0.29	T
Polyphen		0.0070	B
Vest4		0.36
MutPred		0.49		Gain of disorder (P = 0.1223);
MVP		0.75
ClinPred		0.35	T
GERP RS		4.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.14
gMVP		0.38

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs757983603; hg19: chr22-51018250;