16-8781314-G-A

Position:

chr16-8781314-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PVS1_ModeratePM2BS1_Supporting

The NM_001386616.1(ABAT):c.1446G>A(p.Trp482*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000266 in 1,614,132 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000029 ( 0 hom. )

Consequence

ABAT
NM_001386616.1 stop_gained

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.84

Variant links:

Genes affected

ABAT (HGNC:23): (4-aminobutyrate aminotransferase) 4-aminobutyrate aminotransferase (ABAT) is responsible for catabolism of gamma-aminobutyric acid (GABA), an important, mostly inhibitory neurotransmitter in the central nervous system, into succinic semialdehyde. The active enzyme is a homodimer of 50-kD subunits complexed to pyridoxal-5-phosphate. The protein sequence is over 95% similar to the pig protein. GABA is estimated to be present in nearly one-third of human synapses. ABAT in liver and brain is controlled by 2 codominant alleles with a frequency in a Caucasian population of 0.56 and 0.44. The ABAT deficiency phenotype includes psychomotor retardation, hypotonia, hyperreflexia, lethargy, refractory seizures, and EEG abnormalities. Multiple alternatively spliced transcript variants encoding the same protein isoform have been found for this gene. [provided by RefSeq, Jul 2008]

ABAT links:

TMEM186 (HGNC:24530): (transmembrane protein 186) This gene encodes a potential transmembrane protein. [provided by RefSeq, Dec 2012]

TMEM186 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0659 CDS is truncated, and there are 0 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

BS1

Variant frequency is greater than expected in population sas. gnomad4_exome allele frequency = 0.0000287 (42/1461830) while in subpopulation SAS AF= 0.000464 (40/86252). AF 95% confidence interval is 0.00035. There are 0 homozygotes in gnomad4_exome. There are 31 alleles in male gnomad4_exome subpopulation. Median coverage is 34. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ABAT	NM_020686.6 link	c.1387G>A	p.Val463Met	missense_variant	16/16	ENST00000268251.13	NP_065737.2	P80404X5D8S1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ABAT	ENST00000268251.13 link	c.1387G>A	p.Val463Met	missense_variant	16/16	1	NM_020686.6	ENSP00000268251.8		P80404

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152184

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:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000398

AC:

AN:

251420

Hom.:

AF XY:

0.0000589

AC XY:

AN XY:

135892

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:

0.000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000287

AC:

AN:

1461830

Hom.:

Cov.:

AF XY:

0.0000426

AC XY:

AN XY:

727218

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000464

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152302

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74468

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:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ExAC

AF:

0.0000494

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Gamma-aminobutyric acid transaminase deficiency

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 25, 2021

This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 463 of the ABAT protein (p.Val463Met). This variant is present in population databases (rs757912430, gnomAD 0.04%). This variant has not been reported in the literature in individuals affected with ABAT-related conditions. ClinVar contains an entry for this variant (Variation ID: 1016313). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The methionine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

-0.45

BayesDel_noAF

Benign

-0.58

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.22

T;T;.;T

Eigen

Benign

-0.53

Eigen_PC

Benign

-0.36

FATHMM_MKL

Uncertain

0.88

LIST_S2

Uncertain

0.87

.;D;D;.

MetaRNN

Benign

0.056

T;T;T;T

MetaSVM

Benign

-1.1

MutationAssessor

Benign

0.71

N;N;.;N

PrimateAI

Benign

0.34

PROVEAN

Benign

0.64

N;N;N;N

REVEL

Benign

0.032

Sift

Benign

0.24

T;T;T;T

Sift4G

Benign

0.25

T;T;T;T

Polyphen

0.0

B;B;.;B

Vest4

0.083

MutPred

0.46

Loss of catalytic residue at V463 (P = 0.0509);Loss of catalytic residue at V463 (P = 0.0509);.;Loss of catalytic residue at V463 (P = 0.0509);

MVP

0.17

MPC

0.31

ClinPred

0.12

GERP RS

3.1

Varity_R

0.075

gMVP

0.61

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