NM_021815.5:c.81G>A

Variant names:

• chr2-107988236-G-A
• rs1677321281
• NM_021815.5:c.81G>A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_021815.5(SLC5A7):​c.81G>A​(p.Trp27*) variant causes a stop gained change involving the alteration of a conserved nucleotide. 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: SLC5A7 NM_021815.5 stop_gained
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.52

Genes affected

SLC5A7 (HGNC:14025): (solute carrier family 5 member 7) This gene encodes a sodium ion- and chloride ion-dependent high-affinity transporter that mediates choline uptake for acetylcholine synthesis in cholinergic neurons. The protein transports choline from the extracellular space into presynaptic terminals for synthesis into acetylcholine. Increased choline uptake results from increased density of this protein in synaptosomal plasma membranes in response to depolarization of cholinergic terminals. Dysfunction of cholinergic signaling has been implicated in various disorders including depression, attention-deficit disorder, and schizophrenia. An allelic variant of this gene is associated with autosomal dominant distal hereditary motor neuronopathy type VIIA. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2015]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 12 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SLC5A7	NM_021815.5	c.81G>A	p.Trp27*	stop_gained	Exon 2 of 9	ENST00000264047.3	NP_068587.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SLC5A7	ENST00000264047.3	c.81G>A	p.Trp27*	stop_gained	Exon 2 of 9	1	NM_021815.5	ENSP00000264047.2
SLC5A7	ENST00000409059.5	c.81G>A	p.Trp27*	stop_gained	Exon 2 of 9	1		ENSP00000387346.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Feb 18, 2020

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.W27* variant (also known as c.81G>A), located in coding exon 1 of the SLC5A7 gene, results from a G to A substitution at nucleotide position 81. This changes the amino acid from a tryptophan to a stop codon within coding exon 1. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. However, loss of function of SLC5A7 has not been clearly established as a mechanism of disease. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Neuronopathy, distal hereditary motor, type 7A;C4310694:Congenital myasthenic syndrome 20 Uncertain:1

Jul 07, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals affected with SLC5A7-related conditions. 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. ClinVar contains an entry for this variant (Variation ID: 1476505). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Trp27*) in the SLC5A7 gene. It is expected to result in an absent or disrupted protein product. However, the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in SLC5A7 cause disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	43
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.98	D
Vest4		0.84
GERP RS		4.9

Splicing

Name	Calibrated prediction	Score	Prediction
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

LitVar

Other links and lift over

dbSNP: rs1677321281; hg19: chr2-108604692;