12-8822714-G-C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_144670.6(A2ML1):​c.62+1G>C variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,962 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

A2ML1
NM_144670.6 splice_donor, intron

Scores

1
3
3
Splicing: ADA: 0.9999
2

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.905

Publications

2 publications found
Variant links:
Genes affected
A2ML1 (HGNC:23336): (alpha-2-macroglobulin like 1) This gene encodes a member of the alpha-macroglobulin superfamily. The encoded protein is thought to be an N-glycosylated monomeric protein that acts as an inhibitor of several proteases. It has been shown to form covalent interactions with proteases, and has been reported as the p170 antigen recognized by autoantibodies in the autoimmune disease paraneoplastic pemphigus (PNP; PMID:20805888). Mutations in these gene have also been associated with some cases of Noonan syndrome (NS; PMID:24939586) as well as some cases of otitis media (PMID:26121085). Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Aug 2015]
A2ML1-AS1 (HGNC:41022): (A2ML1 antisense RNA 1)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.021305842 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
A2ML1NM_144670.6 linkc.62+1G>C splice_donor_variant, intron_variant Intron 1 of 35 ENST00000299698.12 NP_653271.3 B3KVV6

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
A2ML1ENST00000299698.12 linkc.62+1G>C splice_donor_variant, intron_variant Intron 1 of 35 1 NM_144670.6 ENSP00000299698.7 A8K2U0-1
A2ML1-AS1ENST00000537288.1 linkn.286+7948C>G intron_variant Intron 1 of 1 3

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152224
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000724
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:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000401
AC:
1
AN:
249522
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.0000646
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:
0.00
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461738
Hom.:
0
Cov.:
30
AF XY:
0.00
AC XY:
0
AN XY:
727164
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000597
AC:
2
AN:
33476
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86242
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111890
Other (OTH)
AF:
0.00
AC:
0
AN:
60386
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.038550), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.375
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.0000197
AC:
3
AN:
152224
Hom.:
0
Cov.:
32
AF XY:
0.0000269
AC XY:
2
AN XY:
74370
show subpopulations
African (AFR)
AF:
0.0000724
AC:
3
AN:
41458
American (AMR)
AF:
0.00
AC:
0
AN:
15280
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5202
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10614
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68042
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.575
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:
0.0000416
ExAC
AF:
0.00000827
AC:
1

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

not provided Uncertain:1
Dec 11, 2019
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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. The current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in A2ML1 cause disease. This variant has not been reported in the literature in individuals with A2ML1-related conditions. This variant is present in population databases (rs200764174, ExAC 0.01%). This sequence change affects a donor splice site in intron 1 of the A2ML1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Uncertain
0.034
T
BayesDel_noAF
Uncertain
-0.010
CADD
Uncertain
24
DANN
Benign
0.93
Eigen
Pathogenic
0.72
Eigen_PC
Uncertain
0.49
FATHMM_MKL
Benign
0.74
D
PhyloP100
0.91
GERP RS
2.5
PromoterAI
-0.19
Neutral
Mutation Taster
=19/81
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
0.94
Details are displayed if max score is > 0.2
DS_DL_spliceai
0.94
Position offset: -1

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

Publications

Other links and lift over

dbSNP: rs200764174; hg19: chr12-8975310; API