rs772853856

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3PP5

The NM_000528.4(MAN2B1):​c.1259G>T​(p.Gly420Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000682 in 1,613,386 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G420D) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

MAN2B1
NM_000528.4 missense

Scores

5
10
4

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:4

Conservation

PhyloP100: 4.58

Publications

3 publications found
Variant links:
Genes affected
MAN2B1 (HGNC:6826): (mannosidase alpha class 2B member 1) This gene encodes an enzyme that hydrolyzes terminal, non-reducing alpha-D-mannose residues in alpha-D-mannosides. Its activity is necessary for the catabolism of N-linked carbohydrates released during glycoprotein turnover and it is member of family 38 of glycosyl hydrolases. The full length protein is processed in two steps. First, a 49 aa leader sequence is cleaved off and the remainder of the protein is processed into 3 peptides of 70 kDa, 42 kDa (D) and 13/15 kDa (E). Next, the 70 kDa peptide is further processed into three peptides (A, B and C). The A, B and C peptides are disulfide-linked. Defects in this gene have been associated with lysosomal alpha-mannosidosis. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Mar 2010]
MAN2B1 Gene-Disease associations (from GenCC):
  • alpha-mannosidosis
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Genomics England PanelApp, Myriad Women’s Health, G2P, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.838
PP5
Variant 19-12658113-C-A is Pathogenic according to our data. Variant chr19-12658113-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 208264.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
MAN2B1NM_000528.4 linkc.1259G>T p.Gly420Val missense_variant Exon 10 of 24 ENST00000456935.7 NP_000519.2 O00754-1
MAN2B1NM_001440570.1 linkc.1262G>T p.Gly421Val missense_variant Exon 10 of 24 NP_001427499.1
MAN2B1NM_001173498.2 linkc.1256G>T p.Gly419Val missense_variant Exon 10 of 24 NP_001166969.1 O00754-2A8K6A7
MAN2B1XM_047438841.1 linkc.158G>T p.Gly53Val missense_variant Exon 3 of 17 XP_047294797.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
MAN2B1ENST00000456935.7 linkc.1259G>T p.Gly420Val missense_variant Exon 10 of 24 1 NM_000528.4 ENSP00000395473.2 O00754-1

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152170
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000241
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
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:
0.0000120
AC:
3
AN:
249208
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000579
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.000164
GnomAD4 exome
AF:
0.00000616
AC:
9
AN:
1461216
Hom.:
0
Cov.:
33
AF XY:
0.00000688
AC XY:
5
AN XY:
726916
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.0000894
AC:
4
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52802
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5746
European-Non Finnish (NFE)
AF:
0.00000360
AC:
4
AN:
1111990
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60382
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.503
Heterozygous variant carriers
0
1
2
3
4
5
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:
0.0000131
AC:
2
AN:
152170
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74324
show subpopulations
African (AFR)
AF:
0.0000241
AC:
1
AN:
41452
American (AMR)
AF:
0.0000655
AC:
1
AN:
15278
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:
10610
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68010
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.450
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:
0.0000113
ExAC
AF:
0.0000165
AC:
2

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:4
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Deficiency of alpha-mannosidase Pathogenic:1Uncertain:3
Jul 26, 2023
Baylor Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jun 07, 2012
ClinVar Staff, National Center for Biotechnology Information (NCBI)
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:literature only

- -

May 07, 2022
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Oct 22, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 420 of the MAN2B1 protein (p.Gly420Val). This variant is present in population databases (rs772853856, gnomAD 0.01%). This missense change has been observed in individual(s) with leukodystrophy (PMID: 17404523). ClinVar contains an entry for this variant (Variation ID: 208264). 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 not expected to disrupt MAN2B1 protein function. Experimental studies have shown that this missense change affects MAN2B1 function (PMID: 21505070, 22161967). 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. -

not specified Uncertain:1
Jun 06, 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: MAN2B1 c.1259G>T (p.Gly420Val) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant allele was found at a frequency of 1.2e-05 in 249208 control chromosomes. c.1259G>T has been observed in an individual affected with leukodystrophy who had reduced alpha-mannosidosis activity (Castelnovo_2007). This report does not provide unequivocal conclusions about association of the variant with Deficiency of alpha-mannosidase. Experimental studies evaluating an impact on protein function have reported that the variant is processed into a peptide that localizes to the lysosome, but is not secreted, resulting in <20% of WT activity (e.g. Kuokkanen_2011, Riise Stensland_2012). The following publications have been ascertained in the context of this evaluation (PMID: 17404523, 21505070, 22161967). ClinVar contains an entry for this variant (Variation ID: 208264). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.52
BayesDel_addAF
Pathogenic
0.19
D
BayesDel_noAF
Pathogenic
0.26
CADD
Uncertain
24
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.64
D;.
Eigen
Uncertain
0.36
Eigen_PC
Uncertain
0.40
FATHMM_MKL
Uncertain
0.94
D
LIST_S2
Benign
0.79
T;T
M_CAP
Pathogenic
0.34
D
MetaRNN
Pathogenic
0.84
D;D
MetaSVM
Uncertain
0.021
D
MutationAssessor
Benign
1.6
L;.
PhyloP100
4.6
PrimateAI
Uncertain
0.63
T
PROVEAN
Uncertain
-4.3
D;D
REVEL
Pathogenic
0.72
Sift
Benign
0.035
D;D
Sift4G
Uncertain
0.044
D;D
Polyphen
0.70
P;.
Vest4
0.61
MutPred
0.63
Gain of stability (P = 0.0508);.;
MVP
0.90
MPC
1.4
ClinPred
0.86
D
GERP RS
5.0
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.71
gMVP
0.81
Mutation Taster
=3/97
disease causing

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

Other links and lift over

dbSNP: rs772853856; hg19: chr19-12768927; API