chr16-8779483-G-A

Position:

chr16-8779483-G-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2BP4_ModerateBS1_Supporting

The NM_020686.6(ABAT):c.1274G>A(p.Arg425Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000744 in 1,613,922 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R425L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000075 ( 0 hom. )

Consequence

ABAT
NM_020686.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 3.72

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.122612834).

BS1

Variant frequency is greater than expected in population eas. gnomad4_exome allele frequency = 0.0000746 (109/1461658) while in subpopulation EAS AF= 0.000504 (20/39696). AF 95% confidence interval is 0.000333. There are 0 homozygotes in gnomad4_exome. There are 57 alleles in male gnomad4_exome subpopulation. Median coverage is 32. 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	UniProt
ABAT	NM_020686.6 linkuse as main transcript	c.1274G>A	p.Arg425Gln	missense_variant	15/16	ENST00000268251.13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ABAT	ENST00000268251.13 linkuse as main transcript	c.1274G>A	p.Arg425Gln	missense_variant	15/16	1	NM_020686.6	P1

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152146

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000636

AC:

AN:

251376

Hom.:

AF XY:

0.0000515

AC XY:

AN XY:

135878

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000489

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000746

AC:

109

AN:

1461658

Hom.:

Cov.:

AF XY:

0.0000784

AC XY:

AN XY:

727130

show subpopulations

Gnomad4 AFR exome

AF:

0.0000598

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000504

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000755

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000722

AC:

AN:

152264

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

74452

show subpopulations

Gnomad4 AFR

AF:

0.0000481

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000882

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000579

Hom.:

Bravo

AF:

0.0000491

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000741

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 07, 2022

The c.1274G>A (p.R425Q) alteration is located in exon 15 (coding exon 14) of the ABAT gene. This alteration results from a G to A substitution at nucleotide position 1274, causing the arginine (R) at amino acid position 425 to be replaced by a glutamine (Q). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Gamma-aminobutyric acid transaminase deficiency

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 15, 2022

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 425 of the ABAT protein (p.Arg425Gln). This variant is present in population databases (rs368127499, 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: 572999). 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 glutamine 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

0.075

BayesDel_addAF

Benign

-0.34

BayesDel_noAF

Benign

-0.40

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.24

T;T;.;T;T

Eigen

Benign

-0.36

Eigen_PC

Benign

-0.18

FATHMM_MKL

Uncertain

0.85

LIST_S2

Benign

0.84

.;T;T;.;T

M_CAP

Benign

0.020

MetaRNN

Benign

0.12

T;T;T;T;T

MetaSVM

Benign

-0.78

MutationAssessor

Benign

0.76

N;N;.;N;.

MutationTaster

Benign

0.74

D;D;D;D;D

PrimateAI

Benign

0.28

PROVEAN

Benign

-0.31

N;N;N;N;N

REVEL

Benign

0.11

Sift

Benign

0.55

T;T;T;T;T

Sift4G

Benign

0.42

T;T;T;T;T

Polyphen

0.0020

B;B;.;B;.

Vest4

0.26

MVP

0.74

MPC

0.36

ClinPred

0.057

GERP RS

3.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.038

gMVP

0.65

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

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