chr20-25300853-G-A

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PVS1_ModeratePM2BS1_Supporting

The NM_001042472.3(ABHD12):c.1189C>T(p.Gln397*) variant causes a stop gained change. The variant allele was found at a frequency of 0.0000254 in 1,613,976 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

ABHD12
NM_001042472.3 stop_gained

Scores

Clinical Significance

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

Conservation

PhyloP100: 5.75

Variant links:

Genes affected

ABHD12 (HGNC:15868): (abhydrolase domain containing 12, lysophospholipase) This gene encodes an enzyme that catalyzes the hydrolysis of 2-arachidonoyl glycerol (2-AG), the main endocannabinoid lipid transmitter that acts on cannabinoid receptors, CB1 and CB2. The endocannabinoid system is involved in a wide range of physiological processes, including neurotransmission, mood, appetite, pain appreciation, addiction behavior, and inflammation. Mutations in this gene are associated with the neurodegenerative disease, PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and cataract), resulting from an inborn error of endocannabinoid metabolism. Alternatively spliced transcript variants encoding different isoforms have been noted for this gene.[provided by RefSeq, Jan 2011]

ABHD12 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.00668 CDS is truncated, and there are 0 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

BS1

Variant frequency is greater than expected in population mid. gnomad4_exome allele frequency = 0.0000253 (37/1461766) while in subpopulation MID AF= 0.000694 (4/5764). AF 95% confidence interval is 0.000236. There are 0 homozygotes in gnomad4_exome. There are 23 alleles in male gnomad4_exome subpopulation. Median coverage is 34. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABHD12	NM_001042472.3 link	c.1189C>T	p.Gln397*	stop_gained	Exon 13 of 13	ENST00000339157.10	NP_001035937.1	Q8N2K0-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABHD12	ENST00000339157.10 link	c.1189C>T	p.Gln397*	stop_gained	Exon 13 of 13	2	NM_001042472.3	ENSP00000341408.5		Q8N2K0-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152210

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000361

AC:

AN:

249168

Hom.:

AF XY:

0.0000444

AC XY:

AN XY:

135276

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000981

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000531

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000253

AC:

AN:

1461766

Hom.:

Cov.:

AF XY:

0.0000316

AC XY:

AN XY:

727186

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000928

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000189

Gnomad4 OTH exome

AF:

0.0000662

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152210

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.0000413

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

May 21, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change results in a premature translational stop signal in the ABHD12 gene (p.Gln397*). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 2 amino acids of the ABHD12 protein. This variant is present in population databases (rs745990956, ExAC 0.006%). This variant has not been reported in the literature in individuals with ABHD12-related conditions. ClinVar contains an entry for this variant (Variation ID: 191159). 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. -

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: research

Downgraded to LB based on updated frequency in local population -

not specified

Uncertain:1

Feb 19, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ABHD12 c.1189C>T (p.Gln397X) results in a premature termination codon and although it is not predicted to result in absence of the protein due to nonsense mediated decay, it is expected to cause a truncation of the encoded protein, which is a commonly known mechanism for disease. However, variants downstream of this position have not been classified pathogenic in ClinVar or by our lab. The variant allele was found at a frequency of 3.6e-05 in 249168 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1189C>T has been reported in the literature in the homozygous state in an individual with no apparent symptoms of PHARC (Shamia_2015); however, due to the slowly progressive nature of the disorder and variable phenotype, pathogenicity cannot be ruled out. This report does not provide unequivocal conclusions about association of the variant with PHARC syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 26141664). ClinVar contains an entry for this variant (Variation ID: 191159). Based on the evidence outlined above, the variant was classified as uncertain significance. -

PHARC syndrome

Uncertain:1

Nov 18, 2019

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.081

BayesDel_noAF

Benign

-0.15

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Uncertain

0.36

Eigen_PC

Uncertain

0.43

FATHMM_MKL

Uncertain

0.91

Vest4

0.41

GERP RS

5.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.16

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