rs763339825

chr10-49620490-G-Achr10-49620490-G-Cchr10-49620490-G-T

Variant summary

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

The NM_020549.5(CHAT):c.580-5G>A variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000134 in 1,607,264 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00014 (0 hom.)
• Consequence: CHAT NM_020549.5 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.1145
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -1.45

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]

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 (BayesDel_noAF=-0.88).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHAT	NM_020549.5	c.580-5G>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000337653.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHAT	ENST00000337653.7	c.580-5G>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_020549.5	P2

Frequencies

GnomAD3 genomes AF: 0.0000591 AC: 9 AN: 152170 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

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: 0.000103

Gnomad OTH AF: 0.000479

GnomAD3 exomes AF: 0.0000319 AC: 8 AN: 251112 Hom.: 0 AF XY: 0.0000442 AC XY: 6 AN XY: 135762

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: 0.0000616

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000142 AC: 207 AN: 1455094 Hom.: 0 Cov.: 30 AF XY: 0.000134 AC XY: 97 AN XY: 724336

Gnomad4 AFR exome AF: 0.0000300

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000183

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000591 AC: 9 AN: 152170 Hom.: 0 Cov.: 33 AF XY: 0.0000538 AC XY: 4 AN XY: 74330

Gnomad4 AFR AF: 0.0000241

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: 0.000103

Gnomad4 OTH AF: 0.000479

Alfa AF: 0.0000566 Hom.: 0

Bravo AF: 0.0000302

EpiCase AF: 0.000109

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial infantile myasthenia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 26, 2021

This sequence change falls in intron 3 of the CHAT gene. It does not directly change the encoded amino acid sequence of the CHAT protein. This variant is present in population databases (rs763339825, ExAC 0.006%). This variant has not been reported in the literature in individuals affected with CHAT-related conditions. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jul 20, 2022

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports a deleterious effect on splicing; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.88
Cadd	Benign	16
Dann	Benign	0.34

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.11
dbscSNV1_RF	Benign	0.38
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.98		Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs763339825; hg19: chr10-50828536;