16-8779557-C-T

Position:

chr16-8779557-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_020686.6(ABAT):c.1348C>T(p.Arg450Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000991 in 1,613,972 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000010 ( 0 hom. )

Consequence

ABAT
NM_020686.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.29

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_pathogenic. Variant got 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.968

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ABAT	NM_020686.6 linkuse as main transcript	c.1348C>T	p.Arg450Trp	missense_variant	15/16	ENST00000268251.13	NP_065737.2	P80404X5D8S1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ABAT	ENST00000268251.13 linkuse as main transcript	c.1348C>T	p.Arg450Trp	missense_variant	15/16	1	NM_020686.6	ENSP00000268251.8		P80404

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152160

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000278

AC:

AN:

251440

Hom.:

AF XY:

0.0000368

AC XY:

AN XY:

135900

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000867

Gnomad ASJ exome

AF:

0.0000992

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000653

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000103

AC:

AN:

1461812

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727212

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000894

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000540

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152160

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74342

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

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

Aug 22, 2022

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 450 of the ABAT protein (p.Arg450Trp). This variant is present in population databases (rs748725086, gnomAD 0.009%). 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: 578863). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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

Pathogenic

0.88

BayesDel_addAF

Pathogenic

0.25

BayesDel_noAF

Pathogenic

0.32

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.79

D;D;.;D;D

Eigen

Uncertain

0.65

Eigen_PC

Uncertain

0.53

FATHMM_MKL

Uncertain

0.88

LIST_S2

Uncertain

0.97

.;D;D;.;D

M_CAP

Uncertain

0.16

MetaRNN

Pathogenic

0.97

D;D;D;D;D

MetaSVM

Uncertain

0.52

MutationAssessor

Pathogenic

3.7

H;H;.;H;.

PrimateAI

Uncertain

0.62

PROVEAN

Pathogenic

-7.4

D;D;D;D;D

REVEL

Pathogenic

0.78

Sift

Pathogenic

0.0

D;D;D;D;D

Sift4G

Pathogenic

0.0

D;D;D;D;D

Polyphen

1.0

D;D;.;D;.

Vest4

0.96

MutPred

0.79

Loss of disorder (P = 0.0636);Loss of disorder (P = 0.0636);.;Loss of disorder (P = 0.0636);Loss of disorder (P = 0.0636);

MVP

0.90

MPC

1.1

ClinPred

1.0

GERP RS

4.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.96

gMVP

0.95

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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