16-8768905-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -10 ACMG points: 0P and 10B. BP4_StrongBP6_ModerateBS1

The NM_020686.6(ABAT):c.748C>T(p.Arg250Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000991 in 1,614,154 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R250Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00014 ( 1 hom., cov: 33)

Exomes 𝑓: 0.000094 ( 0 hom. )

Consequence

ABAT
NM_020686.6 missense

Scores

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: 2.32

Publications

4 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: Benign. The variant received -10 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.020848006).

BP6

Variant 16-8768905-C-T is Benign according to our data. Variant chr16-8768905-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 460329.Status of the report is criteria_provided_single_submitter, 1 stars.

BS1

Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.000144 (22/152272) while in subpopulation EAS AF = 0.0029 (15/5174). AF 95% confidence interval is 0.00179. There are 1 homozygotes in GnomAd4. There are 12 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABAT	NM_020686.6 link	c.748C>T	p.Arg250Trp	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.748C>T	p.Arg250Trp	missense_variant	Exon 11 of 16	1	NM_020686.6	ENSP00000268251.8		P80404

Frequencies

GnomAD3 genomes

AF:

0.000145

AC:

AN:

152154

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00289

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000223

AC:

AN:

251482

AF XY:

0.000243

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00272

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000944

AC:

138

AN:

1461882

Hom.:

Cov.:

AF XY:

0.0000990

AC XY:

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.000119

AC:

AN:

33480

American (AMR)

AF:

0.0000447

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00227

AC:

AN:

39698

South Asian (SAS)

AF:

0.000174

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000225

AC:

AN:

1112006

Other (OTH)

AF:

0.0000331

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

AF:

0.000144

AC:

AN:

152272

Hom.:

Cov.:

AF XY:

0.000161

AC XY:

AN XY:

74446

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

41562

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00290

AC:

AN:

5174

South Asian (SAS)

AF:

0.000207

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68020

Other (OTH)

AF:

0.00

AC:

AN:

2114

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

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.000125

ExAC

AF:

0.000222

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Gamma-aminobutyric acid transaminase deficiency

Benign:1

Jan 28, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Uncertain

-0.070

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.66

D;D;.;D;D

Eigen

Benign

-0.098

Eigen_PC

Benign

0.0040

FATHMM_MKL

Uncertain

0.82

LIST_S2

Uncertain

0.96

.;D;D;.;D

M_CAP

Uncertain

0.15

MetaRNN

Benign

0.021

T;T;T;T;T

MetaSVM

Uncertain

-0.19

MutationAssessor

Uncertain

2.6

M;M;.;M;.

PhyloP100

2.3

PrimateAI

Uncertain

0.75

PROVEAN

Pathogenic

-4.7

D;D;D;D;D

REVEL

Uncertain

0.47

Sift

Uncertain

0.021

D;D;D;D;D

Sift4G

Uncertain

0.0070

D;D;D;D;D

Polyphen

0.092

B;B;.;B;.

Vest4

0.50

MutPred

0.45

Gain of ubiquitination at K252 (P = 0.0573);Gain of ubiquitination at K252 (P = 0.0573);.;Gain of ubiquitination at K252 (P = 0.0573);Gain of ubiquitination at K252 (P = 0.0573);

MVP

0.85

MPC

0.32

ClinPred

0.16

GERP RS

3.5

Varity_R

0.48

gMVP

0.87

Mutation Taster

=65/35

polymorphism

(source)

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

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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