10-49620534-C-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2PM5PP3_Strong

The NM_020549.5(CHAT):c.619C>T(p.Arg207Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000744 in 1,613,772 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R207H) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

CHAT
NM_020549.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 3.70

Variant links:

Genes affected

CHAT (HGNC:1912): (choline O-acetyltransferase) This gene encodes an enzyme which catalyzes the biosynthesis of the neurotransmitter acetylcholine. This gene product is a characteristic feature of cholinergic neurons, and changes in these neurons may explain some of the symptoms of Alzheimer's disease. Polymorphisms in this gene have been associated with Alzheimer's disease and mild cognitive impairment. Mutations in this gene are associated with congenital myasthenic syndrome associated with episodic apnea. Multiple transcript variants encoding different isoforms have been found for this gene, and some of these variants have been shown to encode more than one isoform. [provided by RefSeq, May 2010]

CHAT links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 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 chr10-49620535-G-A is described in Lovd as [Likely_pathogenic].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.985

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHAT	NM_020549.5 link	c.619C>T	p.Arg207Cys	missense_variant	Exon 4 of 15	ENST00000337653.7	NP_065574.4	P28329-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHAT	ENST00000337653.7 link	c.619C>T	p.Arg207Cys	missense_variant	Exon 4 of 15	1	NM_020549.5	ENSP00000337103.2		P28329-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152148

Hom.:

Cov.:

show subpopulations

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:

0.00

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251440

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135898

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 SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000684

AC:

AN:

1461624

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727136

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000450

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152148

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74328

show subpopulations

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:

0.00

Bravo

AF:

0.0000113

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Familial infantile myasthenia

Uncertain:2

Dec 08, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 207 of the CHAT protein (p.Arg207Cys). This variant is present in population databases (rs760936252, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with CHAT-related conditions. ClinVar contains an entry for this variant (Variation ID: 577871). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CHAT protein function. 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. -

Kasturba Medical College, Manipal, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

A missense variant, c.619C>T in CHAT (Choline acetyltransferase) gene was identified in a homozygous state in the proband. On segregation, this variant was present in heterozygous state in mother and father. This variant is present in 12 individuals in heterozygous state in gnomAD population database (v4.1.0) and absent from our in-house exome data of 3356 individuals. The variant c.619C>T has been reported in ClinVar as uncertain significance by a single submitter (Variation ID: 577871). In silico tools (CADD_phred, Mutation Taster, ClinPred and REVEL) predict the variant to be disease-causing and affect the protein function. Different amino acid changes at the same position [p.Arg207His (Arredondo et al., 2015; ClinVar database: VCV000289944.21) and p.Arg207Gly (ClinVar database: VCV000806470.29)] have been reported as disease causing and associated with congenital myasthenic syndrome. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.47

BayesDel_addAF

Pathogenic

0.35

BayesDel_noAF

Pathogenic

0.36

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.87

.;.;.;D;.

Eigen

Pathogenic

0.87

Eigen_PC

Pathogenic

0.78

FATHMM_MKL

Uncertain

0.95

LIST_S2

Pathogenic

0.98

.;.;D;D;D

M_CAP

Uncertain

0.26

MetaRNN

Pathogenic

0.99

D;D;D;D;D

MetaSVM

Pathogenic

0.94

MutationAssessor

Pathogenic

4.0

.;.;.;H;.

PrimateAI

Pathogenic

0.80

PROVEAN

Pathogenic

-5.6

D;D;D;D;D

REVEL

Pathogenic

0.89

Sift

Uncertain

0.0040

D;D;D;D;D

Sift4G

Uncertain

0.0030

D;D;D;D;D

Polyphen

1.0

.;.;.;D;.

Vest4

0.94

MutPred

0.93

.;.;.;Gain of catalytic residue at L208 (P = 0.0428);.;

MVP

0.96

MPC

1.0

ClinPred

1.0

GERP RS

5.4

Varity_R

0.88

gMVP

0.89

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over