chr22-49907782-G-A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_024105.4(ALG12):​c.931C>T​(p.Arg311Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000297 in 1,614,020 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. R311R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000030 ( 0 hom. )

Consequence

ALG12
NM_024105.4 missense

Scores

13
5
1

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 9.54

Publications

3 publications found
Variant links:
Genes affected
ALG12 (HGNC:19358): (ALG12 alpha-1,6-mannosyltransferase) This gene encodes a member of the glycosyltransferase 22 family. The encoded protein catalyzes the addition of the eighth mannose residue in an alpha-1,6 linkage onto the dolichol-PP-oligosaccharide precursor (dolichol-PP-Man(7)GlcNAc(2)) required for protein glycosylation. Mutations in this gene have been associated with congenital disorder of glycosylation type Ig (CDG-Ig)characterized by abnormal N-glycosylation. [provided by RefSeq, Jul 2008]
ALG12 Gene-Disease associations (from GenCC):
  • ALG12-congenital disorder of glycosylation
    Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, G2P, ClinGen, Labcorp Genetics (formerly Invitae), PanelApp Australia, Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.994

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
ALG12NM_024105.4 linkc.931C>T p.Arg311Cys missense_variant Exon 7 of 10 ENST00000330817.11 NP_077010.1 Q9BV10A0A024R4V6
ALG12XM_017028936.2 linkc.931C>T p.Arg311Cys missense_variant Exon 7 of 10 XP_016884425.1
ALG12XM_017028937.2 linkc.931C>T p.Arg311Cys missense_variant Exon 7 of 11 XP_016884426.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
ALG12ENST00000330817.11 linkc.931C>T p.Arg311Cys missense_variant Exon 7 of 10 1 NM_024105.4 ENSP00000333813.5 Q9BV10
ALG12ENST00000486602.1 linkc.136C>T p.Arg46Cys missense_variant Exon 1 of 4 3 ENSP00000420630.1 H7C5R7
ALG12ENST00000492791.1 linkn.460C>T non_coding_transcript_exon_variant Exon 3 of 6 3 ENSP00000417387.1 H7C4I6

Frequencies

GnomAD3 genomes
AF:
0.0000263
AC:
4
AN:
152188
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000483
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000119
AC:
3
AN:
251328
AF XY:
0.00000736
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000176
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000301
AC:
44
AN:
1461832
Hom.:
0
Cov.:
31
AF XY:
0.0000303
AC XY:
22
AN XY:
727214
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.0000504
AC:
2
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53364
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000342
AC:
38
AN:
1112012
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.476
Heterozygous variant carriers
0
3
6
10
13
16
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome 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
GnomAD4 genome
AF:
0.0000263
AC:
4
AN:
152188
Hom.:
0
Cov.:
33
AF XY:
0.0000269
AC XY:
2
AN XY:
74338
show subpopulations
African (AFR)
AF:
0.0000483
AC:
2
AN:
41438
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:
5196
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10616
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68038
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
1
1
2
2
3
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:
0.0000180
Hom.:
0
Bravo
AF:
0.00000378
ExAC
AF:
0.0000165
AC:
2
EpiCase
AF:
0.0000545
EpiControl
AF:
0.00

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

ALG12-congenital disorder of glycosylation Uncertain:3
Oct 30, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 311 of the ALG12 protein (p.Arg311Cys). This variant is present in population databases (rs746215829, gnomAD 0.005%). This missense change has been observed in individual(s) with ALG12-congenital disorder of glycosylation (CDG-Ig) (PMID: 15639192). ClinVar contains an entry for this variant (Variation ID: 377465). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt ALG12 protein function with a positive predictive value of 80%. 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. -

Sep 21, 2017
Mayo Clinic Laboratories, Mayo Clinic
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Oct 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Uncertain:1
Nov 04, 2024
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: ALG12 c.931C>T (p.Arg311Cys) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 251328 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.931C>T has been reported in the literature in an individual affected with ALG12-Congenital Disorder Of Glycosylation (Eklund_2005). These data do not allow any conclusion about variant significance. 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: 15639192). ClinVar contains an entry for this variant (Variation ID: 377465). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided Uncertain:1
Jul 13, 2019
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Reported previously, in the compound heterozygous state with another missense variant, in a patient with congenital disorder of glycosylation type Ig (CDG-Ig) (Eklund et al., 2005); Complementation studies demonstrated that wild-type hALG12 was able to correct the biochemical phenotype in fibroblast cells from the affected individual; however functional analysis specifically showing pathogenicity of the R311C variant was not performed and additional studies are needed to validate the functional effect of this specific variant in vivo (Eklund et al., 2005); Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 15639192) -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.57
BayesDel_addAF
Pathogenic
0.39
D
BayesDel_noAF
Pathogenic
0.49
CADD
Pathogenic
31
DANN
Pathogenic
1.0
DEOGEN2
Uncertain
0.69
D
Eigen
Uncertain
0.53
Eigen_PC
Uncertain
0.45
FATHMM_MKL
Pathogenic
1.0
D
LIST_S2
Pathogenic
0.99
D
M_CAP
Pathogenic
0.58
D
MetaRNN
Pathogenic
0.99
D
MetaSVM
Uncertain
0.52
D
MutationAssessor
Pathogenic
3.8
H
PhyloP100
9.5
PrimateAI
Uncertain
0.74
T
PROVEAN
Pathogenic
-7.4
D
REVEL
Pathogenic
0.90
Sift
Pathogenic
0.0
D
Sift4G
Pathogenic
0.0010
D
Polyphen
1.0
D
Vest4
0.99
MutPred
0.97
Gain of sheet (P = 0.0827);
MVP
0.97
MPC
0.77
ClinPred
1.0
D
GERP RS
4.3
PromoterAI
-0.027
Neutral
Varity_R
0.89
gMVP
0.97
Mutation Taster
=0/100
disease causing

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

Publications

Other links and lift over

dbSNP: rs746215829; hg19: chr22-50301430; COSMIC: COSV58207721; COSMIC: COSV58207721; API