chr16-8768906-G-A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BS2

The NM_020686.6(ABAT):c.749G>A(p.Arg250Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000421 in 1,613,996 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts 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. R250G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000044 ( 2 hom. )

Consequence

ABAT
NM_020686.6 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 4.21

Publications

1 publications found

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 Gene-Disease associations (from GenCC):

GABA aminotransaminase deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, PanelApp Australia, Orphanet, G2P
genetic developmental and epileptic encephalopathy
Inheritance: AR Classification: MODERATE Submitted by: ClinGen

ABAT links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BS2

High Homozygotes in GnomAdExome4 at 2 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABAT	NM_020686.6 link	c.749G>A	p.Arg250Gln	missense_variant	Exon 11 of 16	ENST00000268251.13	NP_065737.2	P80404X5D8S1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABAT	ENST00000268251.13 link	c.749G>A	p.Arg250Gln	missense_variant	Exon 11 of 16	1	NM_020686.6	ENSP00000268251.8		P80404

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152110

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

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

GnomAD2 exomes

AF:

0.0000795

AC:

AN:

251484

AF XY:

0.0000956

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000438

AC:

AN:

1461886

Hom.:

Cov.:

AF XY:

0.0000550

AC XY:

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.0000597

AC:

AN:

33480

American (AMR)

AF:

0.000246

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39698

South Asian (SAS)

AF:

0.000232

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000243

AC:

AN:

1112010

Other (OTH)

AF:

0.0000497

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.481

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152110

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74288

show subpopulations

African (AFR)

AF:

0.0000724

AC:

AN:

41428

American (AMR)

AF:

0.00

AC:

AN:

15258

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000416

ExAC

AF:

0.000107

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Gamma-aminobutyric acid transaminase deficiency

Uncertain:1

Aug 04, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt ABAT protein function. ClinVar contains an entry for this variant (Variation ID: 460330). This variant has not been reported in the literature in individuals affected with ABAT-related conditions. This variant is present in population databases (rs375002262, gnomAD 0.03%). This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 250 of the ABAT protein (p.Arg250Gln). -

not provided

Uncertain:1

Breakthrough Genomics, Breakthrough Genomics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:not provided

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.074

BayesDel_addAF

Benign

-0.14

BayesDel_noAF

Benign

-0.14

CADD

Benign

(source)

DANN

Benign

0.94

DEOGEN2

Benign

0.18

T;T;.;T;T

Eigen

Benign

-0.42

Eigen_PC

Benign

-0.16

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.94

.;D;D;.;D

M_CAP

Benign

0.065

MetaRNN

Benign

0.15

T;T;T;T;T

MetaSVM

Benign

-0.70

MutationAssessor

Benign

0.21

N;N;.;N;.

PhyloP100

4.2

PrimateAI

Uncertain

0.61

PROVEAN

Benign

-0.30

N;N;N;N;N

REVEL

Uncertain

0.36

Sift

Benign

0.73

T;T;T;T;T

Sift4G

Benign

0.82

T;T;T;T;T

Polyphen

0.0070

B;B;.;B;.

Vest4

0.39

MutPred

0.40

Loss of helix (P = 0.0558);Loss of helix (P = 0.0558);.;Loss of helix (P = 0.0558);Loss of helix (P = 0.0558);

MVP

0.70

MPC

0.36

ClinPred

0.063

GERP RS

4.8

Varity_R

0.084

gMVP

0.76

Mutation Taster

=77/23

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.21

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.21

Position offset: 2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over