chr9-136676681-C-G

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PVS1_StrongPM2PP5_Very_Strong

The NM_006412.4(AGPAT2):​c.493-1G>C variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000186 in 1,613,232 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

AGPAT2
NM_006412.4 splice_acceptor, intron

Scores

4
2
1
Splicing: ADA: 1.000
2

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3O:1

Conservation

PhyloP100: 6.87

Publications

5 publications found
Variant links:
Genes affected
AGPAT2 (HGNC:325): (1-acylglycerol-3-phosphate O-acyltransferase 2) This gene encodes a member of the 1-acylglycerol-3-phosphate O-acyltransferase family. The protein is located within the endoplasmic reticulum membrane and converts lysophosphatidic acid to phosphatidic acid, the second step in de novo phospholipid biosynthesis. Mutations in this gene have been associated with congenital generalized lipodystrophy (CGL), or Berardinelli-Seip syndrome, a disease characterized by a near absence of adipose tissue and severe insulin resistance. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. [provided by RefSeq, Jul 2008]
AGPAT2 Gene-Disease associations (from GenCC):
  • congenital generalized lipodystrophy type 1
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
  • Berardinelli-Seip congenital lipodystrophy
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • neonatal diabetes mellitus
    Inheritance: AR Classification: LIMITED Submitted by: Genomics England PanelApp

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.11469534 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.1, offset of 7, new splice context is: cctctccctgcacctcaaAGtgt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 9-136676681-C-G is Pathogenic according to our data. Variant chr9-136676681-C-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 6630.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
AGPAT2NM_006412.4 linkc.493-1G>C splice_acceptor_variant, intron_variant Intron 3 of 5 ENST00000371696.7 NP_006403.2
AGPAT2NM_001012727.2 linkc.492+280G>C intron_variant Intron 3 of 4 NP_001012745.1
AGPAT2XM_047422636.1 linkc.184-1G>C splice_acceptor_variant, intron_variant Intron 3 of 5 XP_047278592.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
AGPAT2ENST00000371696.7 linkc.493-1G>C splice_acceptor_variant, intron_variant Intron 3 of 5 1 NM_006412.4 ENSP00000360761.2
AGPAT2ENST00000371694.7 linkc.492+280G>C intron_variant Intron 3 of 4 1 ENSP00000360759.3
AGPAT2ENST00000472820.1 linkn.421-1G>C splice_acceptor_variant, intron_variant Intron 1 of 3 1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152208
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000654
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
GnomAD2 exomes
AF:
0.00000399
AC:
1
AN:
250564
AF XY:
0.00000737
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.000164
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461024
Hom.:
0
Cov.:
31
AF XY:
0.00000138
AC XY:
1
AN XY:
726808
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33472
American (AMR)
AF:
0.0000224
AC:
1
AN:
44716
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26132
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39694
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86232
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52872
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111754
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60384
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152208
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74352
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41458
American (AMR)
AF:
0.0000654
AC:
1
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5194
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10632
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68014
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.625
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:3Other:1
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Congenital generalized lipodystrophy type 1 Pathogenic:3Other:1
Mar 04, 2013
Unidad de Genómica Médica UC, Pontificia Universidad Católica de Chile
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:research

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by extreme reduction of white adipose tissue (WAT) mass. CGL type 1 is the most frequent form and is caused by mutations in AGPAT2. Genetic and clinical studies were performed in two affected sisters of a Chilean family. These patients have notoriously dissimilar metabolic abnormalities that correlate with differential levels of circulating leptin and soluble leptin receptor fraction. Sequencing of AGPAT2 exons and exon-intron boundaries revealed two homozygous mutations in both sisters. Intronic c.493-1G>C mutation destroy a conserved splicing site that likely leads to exon 4 skipping and deletion of whole AGPAT2 substrate binding domain. In silico protein modeling provided insights of the mechanisms of lack of catalytic activity owing to both mutations. -

Jun 01, 2004
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Feb 05, 2022
DASA
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.493-1G>C variant is located in a canonical splice-site, and it is not predicted the protein reading frame alteration, however, occur in a critical region and the variant disrupts <10% of protein - PVS1_moderate. This sequence change has been observed in affected individual(s) and ClinVar contains an entry for this variant (ClinVar ID: 6630; PMID: 24498038, 15181077) - PS4_supporting. The variant is present at low allele frequencies population databases (rs606231168 – gnomAD 0.00006570%; ABraOM no frequency - http://abraom.ib.usp.br/) - PM2_supporting. The c.493-1G>C was detected in trans with a pathogenic variant (PMID: 24498038) - PM3. In summary, the currently available evidence indicates that the variant is likely pathogenic. -

-
GeneReviews
Significance:not provided
Review Status:no classification provided
Collection Method:literature only

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.53
D
BayesDel_noAF
Pathogenic
0.15
CADD
Pathogenic
33
DANN
Uncertain
0.99
Eigen
Pathogenic
1.0
Eigen_PC
Pathogenic
0.81
FATHMM_MKL
Uncertain
0.95
D
PhyloP100
6.9
GERP RS
3.7
Mutation Taster
=7/93
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
0.99
Details are displayed if max score is > 0.2
DS_AG_spliceai
0.45
Position offset: -8
DS_AL_spliceai
0.99
Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs606231168; hg19: chr9-139571133; API