NM_020549.5:c.920C>G

Variant names:

• chr10-49625640-C-G
• rs748250869
• NM_020549.5:c.920C>G

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_020549.5(CHAT):​c.920C>G​(p.Ala307Gly) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CHAT NM_020549.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.15
• Publications: 1 publications found

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 Gene-Disease associations (from GenCC):

• congenital myasthenic syndrome 6

  Inheritance: AR Classification: STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• presynaptic congenital myasthenic syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 4 uncertain in NM_020549.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.762

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020549.5. 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
	CHAT	NM_020549.5	MANE Select	c.920C>G	p.Ala307Gly	missense	Exon 6 of 15	NP_065574.4
	CHAT	NM_001142933.2		c.674C>G	p.Ala225Gly	missense	Exon 7 of 16	NP_001136405.2
	CHAT	NM_001142929.2		c.566C>G	p.Ala189Gly	missense	Exon 6 of 15	NP_001136401.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHAT	ENST00000337653.7	TSL:1 MANE Select	c.920C>G	p.Ala307Gly	missense	Exon 6 of 15	ENSP00000337103.2
	CHAT	ENST00000395562.2	TSL:1	c.674C>G	p.Ala225Gly	missense	Exon 7 of 16	ENSP00000378929.2
	CHAT	ENST00000339797.5	TSL:1	c.566C>G	p.Ala189Gly	missense	Exon 6 of 15	ENSP00000343486.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Familial infantile myasthenia (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.71	D
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Uncertain	0.13	D
MetaRNN	Pathogenic	0.76	D
MetaSVM	Pathogenic	0.83	D
MutationAssessor	Pathogenic	3.2	M
PhyloP100		6.2
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-3.3	D
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0030	D
Polyphen		0.98	D
Vest4		0.64
MutPred		0.59		Loss of sheet (P = 0.1501)
MVP		0.94
MPC		0.83
ClinPred		0.99	D
GERP RS		5.3
Varity_R		0.95
gMVP		0.70
Mutation Taster		=14/86	disease causing

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

Other links and lift over

dbSNP: rs748250869; hg19: chr10-50833686;