16-8735765-G-T

Variant names:

• chr16-8735765-G-T
• rs531783337
• NM_020686.6:c.26G>T

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_020686.6(ABAT):​c.26G>T​(p.Arg9Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000687 in 1,455,080 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R9H) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: ABAT NM_020686.6 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.739
• 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: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.14218187).

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.26G>T	p.Arg9Leu	missense	Exon 2 of 16	NP_065737.2
	ABAT	NM_001386615.1		c.26G>T	p.Arg9Leu	missense	Exon 2 of 17	NP_001373544.1
	ABAT	NM_001386616.1		c.26G>T	p.Arg9Leu	missense	Exon 2 of 16	NP_001373545.1	H3BNQ7

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABAT	ENST00000268251.13	TSL:1 MANE Select	c.26G>T	p.Arg9Leu	missense	Exon 2 of 16	ENSP00000268251.8	P80404
	ABAT	ENST00000569156.5	TSL:1	c.26G>T	p.Arg9Leu	missense	Exon 2 of 16	ENSP00000454963.1	H3BNQ7
	ABAT	ENST00000566590.5	TSL:1	n.26G>T		non_coding_transcript_exon	Exon 2 of 15	ENSP00000455198.1	H3BP84

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1455080 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 723162

African (AFR) AF: 0.00 AC: 0 AN: 33454

American (AMR) AF: 0.00 AC: 0 AN: 43934

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25892

East Asian (EAS) AF: 0.00 AC: 0 AN: 39602

South Asian (SAS) AF: 0.00 AC: 0 AN: 84650

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 9.02e-7 AC: 1 AN: 1109214

Other (OTH) AF: 0.00 AC: 0 AN: 60152

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.017	T
BayesDel_noAF	Benign	-0.21
CADD	Benign	15
DANN	Uncertain	0.98
DEOGEN2	Benign	0.034	T
Eigen	Benign	-0.85
Eigen_PC	Benign	-0.86
FATHMM_MKL	Benign	0.32	N
LIST_S2	Benign	0.80	T
M_CAP	Benign	0.034	D
MetaRNN	Benign	0.14	T
MetaSVM	Benign	-0.68	T
MutationAssessor	Benign	0.20	N
PhyloP100		0.74
PrimateAI	Benign	0.26	T
PROVEAN	Benign	-1.1	N
REVEL	Benign	0.28
Sift	Uncertain	0.0080	D
Sift4G	Benign	0.15	T
Polyphen		0.062	B
Vest4		0.45
MutPred		0.41		Loss of MoRF binding (P = 0.0176)
MVP		0.81
MPC		0.38
ClinPred		0.15	T
GERP RS		0.63
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.089
gMVP		0.38
Mutation Taster		=98/2	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

Other links and lift over

dbSNP: rs531783337; hg19: chr16-8829622;