10-49610751-C-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_003055.3(SLC18A3):c.11C>G(p.Ala4Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000393 in 1,524,986 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 (★). Synonymous variant affecting the same amino acid position (i.e. A4A) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 34)
  • Exomes 𝑓: 0.0000036 (0 hom.)
• Consequence: SLC18A3 NM_003055.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0710

Genes affected

SLC18A3 (HGNC:10936): (solute carrier family 18 member A3) This gene is a member of the vesicular amine transporter family. The encoded transmembrane protein transports acetylcholine into secretory vesicles for release into the extracellular space. Acetylcholine transport utilizes a proton gradient established by a vacuolar ATPase. This gene is located within the first intron of the choline acetyltransferase gene. [provided by RefSeq, Jul 2008]

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]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.052678347).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SLC18A3	NM_003055.3	c.11C>G	p.Ala4Gly	missense_variant	1/1	ENST00000374115.5
CHAT	NM_020984.4	c.-69+1552C>G		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SLC18A3	ENST00000374115.5	c.11C>G	p.Ala4Gly	missense_variant	1/1		NM_003055.3	P1
CHAT	ENST00000339797.5	c.-69+1552C>G		intron_variant		1		A2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152226 Hom.: 0 Cov.: 34

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000364 AC: 5 AN: 1372760 Hom.: 0 Cov.: 79 AF XY: 0.00000296 AC XY: 2 AN XY: 675698

Gnomad4 AFR exome AF: 0.0000322

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: 0.00000373

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152226 Hom.: 0 Cov.: 34 AF XY: 0.0000134 AC XY: 1 AN XY: 74364

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: 0.0000147

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 13, 2022

This sequence change replaces alanine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 4 of the SLC18A3 protein (p.Ala4Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SLC18A3-related conditions. 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. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.068
BayesDel_addAF	Benign	-0.35	T
BayesDel_noAF	Benign	-0.75
Cadd	Benign	1.3
Dann	Benign	0.84
DEOGEN2	Benign	0.12	T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.17	N
LIST_S2	Benign	0.32	T
M_CAP	Benign	0.048	D
MetaRNN	Benign	0.053	T
MetaSVM	Benign	-0.89	T
MutationAssessor	Benign	0.76	N
MutationTaster	Benign	1.0	N;N
PrimateAI	Uncertain	0.56	T
PROVEAN	Benign	0.060	N
REVEL	Benign	0.058
Sift	Benign	0.37	T
Sift4G	Benign	0.53	T
Polyphen		0.0	B
Vest4		0.094
MutPred		0.037		Gain of glycosylation at S3 (P = 0.054);
MVP		0.23
ClinPred		0.028	T
GERP RS		-2.5
Varity_R		0.036
gMVP		0.21

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

Other links and lift over

dbSNP: rs1838268773; hg19: chr10-50818797;