rs121907932

Positions:

chr22-49910466-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2PP3_ModeratePP5_Very_Strong

The NM_024105.4(ALG12):c.437G>A(p.Arg146Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000123 in 1,613,640 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R146W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00014 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00012 ( 0 hom. )

Consequence

ALG12
NM_024105.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 7.77

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.934

PP5

Variant 22-49910466-C-T is Pathogenic according to our data. Variant chr22-49910466-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3435.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr22-49910466-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
ALG12	NM_024105.4 linkuse as main transcript	c.437G>A	p.Arg146Gln	missense_variant	4/10	ENST00000330817.11
ALG12	XM_017028936.2 linkuse as main transcript	c.437G>A	p.Arg146Gln	missense_variant	4/10
ALG12	XM_017028937.2 linkuse as main transcript	c.437G>A	p.Arg146Gln	missense_variant	4/11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALG12	ENST00000330817.11 linkuse as main transcript	c.437G>A	p.Arg146Gln	missense_variant	4/10	1	NM_024105.4	P1

Frequencies

GnomAD3 genomes

AF:

0.000145

AC:

AN:

152214

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000723

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.000188

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000221

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000116

AC:

AN:

250992

Hom.:

AF XY:

0.000118

AC XY:

AN XY:

135774

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.000203

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.000121

AC:

177

AN:

1461426

Hom.:

Cov.:

AF XY:

0.000110

AC XY:

AN XY:

727008

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.000112

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.0000944

Gnomad4 NFE exome

AF:

0.000134

Gnomad4 OTH exome

AF:

0.000232

GnomAD4 genome

AF:

0.000145

AC:

AN:

152214

Hom.:

Cov.:

AF XY:

0.000134

AC XY:

AN XY:

74366

show subpopulations

Gnomad4 AFR

AF:

0.0000723

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.000188

Gnomad4 NFE

AF:

0.000221

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000182

Hom.:

Bravo

AF:

0.000219

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000148

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000296

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

ALG12-congenital disorder of glycosylation

Pathogenic:5

Pathogenic, no assertion criteria provided	literature only	OMIM	Jun 15, 2007	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Sep 07, 2022	Variant summary: ALG12 c.437G>A (p.Arg146Gln) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00012 in 250992 control chromosomes (gnomAD). c.437G>A has been reported in the literature in individuals affected with Congenital Disorder Of Glycosylation (Grubenmann_2002, Kranz_2007, Normand_2018, Scott_2022). These data indicate that the variant is likely to be associated with disease. A functional yeast complementation assay showed that the variant had very weak rescue ability in an alg12 deficient yeast strain grown with hygromycin B, indicating loss of function (Grubenmann_2002). Four ClinVar submitters have assessed the variant since 2014: one classified the variant as uncertain significance, one as likely pathogenic, and two as pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Daryl Scott Lab, Baylor College of Medicine	Nov 11, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Sep 01, 2017	This mutation has been previously reported as disease-causing and has been found once in our laboratory in trans with a deleterious frameshift mutation in a fetus with cystic hygroma, VSD, diaphragmatic hernia, brain malformations, and micrognathia; a previous fetus was similarly affected (not tested). -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 21, 2024	This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 146 of the ALG12 protein (p.Arg146Gln). This variant is present in population databases (rs121907932, gnomAD 0.02%). This missense change has been observed in individual(s) with clinical features of congenital disorders of glycosylation (PMID: 12217961, 17506107, 30266093, 33461977). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 3435). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt ALG12 protein function with a positive predictive value of 80%. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on ALG12 function (PMID: 12217961). For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Oct 13, 2017

- -

ALG12-related disorder

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jan 03, 2023

The ALG12 c.437G>A variant is predicted to result in the amino acid substitution p.Arg146Gln. This variant has been reported to be causative for autosomal recessive congenital disorder of glycosylation type 1g (CDG1G; OMIM: #607143; Grubenmann et al. 2002. PubMed ID: 12217961; Kranz et al. 2007. PubMed ID: 17506107; Normand et al. 2018. PubMed ID: 30266093). This variant is reported in 0.019% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/22-50304114-C-T). Given the evidence, we interpret c.437G>A (p.Arg146Gln) as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.61

BayesDel_addAF

Pathogenic

0.17

BayesDel_noAF

Pathogenic

0.30

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.70

Eigen

Pathogenic

0.79

Eigen_PC

Pathogenic

0.69

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Pathogenic

0.99

M_CAP

Uncertain

0.26

MetaRNN

Pathogenic

0.93

MetaSVM

Uncertain

0.45

MutationAssessor

Pathogenic

3.8

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.66

PROVEAN

Uncertain

-3.8

REVEL

Pathogenic

0.77

Sift

Uncertain

0.0030

Sift4G

Uncertain

0.0050

Polyphen

0.99

Vest4

0.99

MVP

0.90

MPC

0.56

ClinPred

0.96

GERP RS

4.6

Varity_R

0.85

gMVP

0.88

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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