16-8735794-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_020686.6(ABAT):c.55C>T(p.Arg19Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000678 in 1,605,756 control chromosomes in the GnomAD database, including 8 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R19S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0032 ( 3 hom., cov: 32)

Exomes 𝑓: 0.00042 ( 5 hom. )

Consequence

ABAT
NM_020686.6 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:3

Conservation

PhyloP100: 0.331

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 was made for transcript

Our verdict: Benign. The variant received -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.008483738).

BP6

Variant 16-8735794-C-T is Benign according to our data. Variant chr16-8735794-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 235649.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=1, Benign=2}.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00318 (484/152232) while in subpopulation AFR AF = 0.0108 (449/41536). AF 95% confidence interval is 0.00998. There are 3 homozygotes in GnomAd4. There are 225 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position FAILED quality control check.

BS2

High Homozygotes in GnomAd4 at 3 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABAT	NM_020686.6 link	c.55C>T	p.Arg19Cys	missense_variant	Exon 2 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.55C>T	p.Arg19Cys	missense_variant	Exon 2 of 16	1	NM_020686.6	ENSP00000268251.8		P80404

Frequencies

GnomAD3 genomes

AF:

0.00317

AC:

482

AN:

152114

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0108

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00125

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000386

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.0000943

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00431

GnomAD2 exomes

AF:

0.000935

AC:

220

AN:

235212

AF XY:

0.000668

show subpopulations

Gnomad AFR exome

AF:

0.0111

Gnomad AMR exome

AF:

0.000693

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000674

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000151

Gnomad OTH exome

AF:

0.000347

GnomAD4 exome

AF:

0.000416

AC:

604

AN:

1453524

Hom.:

Cov.:

AF XY:

0.000370

AC XY:

267

AN XY:

722210

show subpopulations

Gnomad4 AFR exome

AF:

0.0105

AC:

352

AN:

33440

Gnomad4 AMR exome

AF:

0.000595

AC:

AN:

43696

Gnomad4 ASJ exome

AF:

0.00

AC:

AN:

25886

Gnomad4 EAS exome

AF:

0.000430

AC:

AN:

39578

Gnomad4 SAS exome

AF:

0.000178

AC:

AN:

84454

Gnomad4 FIN exome

AF:

0.00

AC:

AN:

52172

Gnomad4 NFE exome

AF:

0.000127

AC:

141

AN:

1108396

Gnomad4 Remaining exome

AF:

0.000815

AC:

AN:

60142

Heterozygous variant carriers

132

165

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Exome Het

Exome Hom

Variant carriers

100

<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:

0.00318

AC:

484

AN:

152232

Hom.:

Cov.:

AF XY:

0.00302

AC XY:

225

AN XY:

74446

show subpopulations

Gnomad4 AFR

AF:

0.0108

AC:

0.0108099

AN:

0.0108099

Gnomad4 AMR

AF:

0.00124

AC:

0.00124346

AN:

0.00124346

Gnomad4 ASJ

AF:

0.00

AC:

AN:

Gnomad4 EAS

AF:

0.000386

AC:

0.000386399

AN:

0.000386399

Gnomad4 SAS

AF:

0.000207

AC:

0.000207383

AN:

0.000207383

Gnomad4 FIN

AF:

0.0000943

AC:

0.0000942507

AN:

0.0000942507

Gnomad4 NFE

AF:

0.0000294

AC:

0.0000294023

AN:

0.0000294023

Gnomad4 OTH

AF:

0.00426

AC:

0.00426136

AN:

0.00426136

Heterozygous variant carriers

116

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

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:

0.00109

Hom.:

Bravo

AF:

0.00340

ESP6500AA

AF:

0.0112

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.00101

AC:

122

Asia WGS

AF:

0.00173

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Gamma-aminobutyric acid transaminase deficiency

Uncertain:1Benign:1

Jan 15, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Benign:2

Mar 01, 2022

CeGaT Center for Human Genetics Tuebingen

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

ABAT: BP4, BS1, BS2 -

May 19, 2016

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

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

0.099

BayesDel_addAF

Benign

-0.34

BayesDel_noAF

Benign

-0.25

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Benign

0.062

T;T;.;T;T;.;.;T;T

Eigen

Benign

-0.48

Eigen_PC

Benign

-0.48

FATHMM_MKL

Benign

0.11

LIST_S2

Benign

0.76

.;T;T;T;T;T;T;.;T

MetaRNN

Benign

0.0085

T;T;T;T;T;T;T;T;T

MetaSVM

Benign

-0.42

MutationAssessor

Benign

2.0

M;.;.;.;M;.;.;M;.

PrimateAI

Benign

0.25

PROVEAN

Benign

-1.4

N;N;D;N;N;N;N;N;N

REVEL

Uncertain

0.31

Sift

Benign

0.099

T;T;T;T;T;T;T;T;D

Sift4G

Uncertain

0.041

D;T;D;T;D;D;D;D;D

Polyphen

0.0020

B;.;.;.;B;.;.;B;.

Vest4

0.20

MVP

0.78

MPC

0.42

ClinPred

0.010

GERP RS

4.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.065

gMVP

0.47

Mutation Taster

=99/1

polymorphism

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