NM_020686.6:c.817-6A>G

Variant names:

• chr16-8772774-A-G
• rs140106845
• NM_020686.6:c.817-6A>G

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_020686.6(ABAT):​c.817-6A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000543 in 1,614,044 control chromosomes in the GnomAD database, including 7 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0030 (3 hom., cov: 31)
  • Exomes 𝑓: 0.00029 (4 hom.)
• Consequence: ABAT NM_020686.6 splice_region, intron
• Scores: Splicing: ADA: 0.0001490
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: 0.0180

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]

ACMG classification

Verdict is Benign. Variant got -20 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.82).
• BP6: Variant 16-8772774-A-G is Benign according to our data. Variant chr16-8772774-A-G is described in ClinVar as [Benign]. Clinvar id is 529796.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00298 (454/152236) while in subpopulation AFR AF= 0.0104 (431/41544). AF 95% confidence interval is 0.00957. There are 3 homozygotes in gnomad4. There are 207 alleles in male gnomad4 subpopulation. Median coverage is 31. This position pass quality control queck.
• 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	c.817-6A>G		splice_region_variant, intron_variant	Intron 11 of 15	ENST00000268251.13	NP_065737.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABAT	ENST00000268251.13	c.817-6A>G		splice_region_variant, intron_variant	Intron 11 of 15	1	NM_020686.6	ENSP00000268251.8

Frequencies

GnomAD3 genomes AF: 0.00298 AC: 454 AN: 152118 Hom.: 3 Cov.: 31

Gnomad AFR AF: 0.0104

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000917

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: 0.0000441

Gnomad OTH AF: 0.00287

GnomAD3 exomes AF: 0.000788 AC: 198 AN: 251420 Hom.: 1 AF XY: 0.000618 AC XY: 84 AN XY: 135878

Gnomad AFR exome AF: 0.0108

Gnomad AMR exome AF: 0.000549

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.000326

GnomAD4 exome AF: 0.000289 AC: 422 AN: 1461808 Hom.: 4 Cov.: 32 AF XY: 0.000257 AC XY: 187 AN XY: 727202

Gnomad4 AFR exome AF: 0.0109

Gnomad4 AMR exome AF: 0.000514

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.000414

GnomAD4 genome AF: 0.00298 AC: 454 AN: 152236 Hom.: 3 Cov.: 31 AF XY: 0.00278 AC XY: 207 AN XY: 74432

Gnomad4 AFR AF: 0.0104

Gnomad4 AMR AF: 0.000916

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00284

Alfa AF: 0.00142 Hom.: 0

Bravo AF: 0.00328

ClinVar

Significance: Benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Gamma-aminobutyric acid transaminase deficiency Benign:2

Jan 27, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 16, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Benign:2

Feb 29, 2016

Mayo Clinic Laboratories, Mayo Clinic

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Breakthrough Genomics, Breakthrough Genomics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.82
CADD	Benign	3.7
DANN	Benign	0.46
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00015
dbscSNV1_RF	Benign	0.0060
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

Other links and lift over

dbSNP: rs140106845; hg19: chr16-8866631;