chr16-8674626-C-G

Variant names:

• chr16-8674626-C-G
• rs937622924
• NM_020686.6:c.-127C>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_020686.6(ABAT):​c.-127C>G variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000394 in 152,220 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: ABAT NM_020686.6 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.581
• Publications: 0 publications found

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: Ambry Genetics, Labcorp Genetics (formerly Invitae), PanelApp Australia, G2P, Orphanet
• genetic developmental and epileptic encephalopathy

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.7).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020686.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABAT	NM_020686.6	MANE Select	c.-127C>G		5_prime_UTR	Exon 1 of 16	NP_065737.2
	ABAT	NM_001386615.1		c.-127C>G		5_prime_UTR	Exon 1 of 17	NP_001373544.1
	ABAT	NM_001386602.1		c.-228C>G		5_prime_UTR	Exon 1 of 17	NP_001373531.1	X5D8S1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABAT	ENST00000268251.13	TSL:1 MANE Select	c.-127C>G		5_prime_UTR	Exon 1 of 16	ENSP00000268251.8	P80404
	ABAT	ENST00000909342.1		c.-228C>G		5_prime_UTR	Exon 1 of 17	ENSP00000579401.1
	ABAT	ENST00000909343.1		c.-239C>G		5_prime_UTR	Exon 1 of 17	ENSP00000579402.1

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152220 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.0000588

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 40 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 28

African (AFR) AF: 0.00 AC: 0 AN: 2

American (AMR) AC: 0 AN: 0

Ashkenazi Jewish (ASJ) AC: 0 AN: 0

East Asian (EAS) AC: 0 AN: 0

South Asian (SAS) AC: 0 AN: 0

European-Finnish (FIN) AC: 0 AN: 0

Middle Eastern (MID) AC: 0 AN: 0

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 38

Other (OTH) AC: 0 AN: 0

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152220 Hom.: 0 Cov.: 32 AF XY: 0.0000538 AC XY: 4 AN XY: 74358

African (AFR) AF: 0.00 AC: 0 AN: 41464

American (AMR) AF: 0.000131 AC: 2 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000588 AC: 4 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000756

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Gamma-aminobutyric acid transaminase deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.70
CADD	Benign	13
DANN	Benign	0.84
PhyloP100		-0.58
PromoterAI		0.084	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

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

Other links and lift over

dbSNP: rs937622924; hg19: chr16-8768483;