rs747721968

Variant summary

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

The NM_000528.4(MAN2B1):​c.1501T>A​(p.Cys501Ser) variant causes a missense change. The variant allele was found at a frequency of 0.00000558 in 1,613,560 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. C501C) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

MAN2B1
NM_000528.4 missense

Scores

6
12
1

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 4.98

Publications

7 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: 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, 0.968

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
MAN2B1NM_000528.4 linkc.1501T>A p.Cys501Ser missense_variant Exon 12 of 24 ENST00000456935.7 NP_000519.2
MAN2B1NM_001440570.1 linkc.1504T>A p.Cys502Ser missense_variant Exon 12 of 24 NP_001427499.1
MAN2B1NM_001173498.2 linkc.1498T>A p.Cys500Ser missense_variant Exon 12 of 24 NP_001166969.1
MAN2B1XM_047438841.1 linkc.400T>A p.Cys134Ser missense_variant Exon 5 of 17 XP_047294797.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
MAN2B1ENST00000456935.7 linkc.1501T>A p.Cys501Ser missense_variant Exon 12 of 24 1 NM_000528.4 ENSP00000395473.2

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152210
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000482
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:
0.000478
GnomAD2 exomes
AF:
0.00000399
AC:
1
AN:
250324
AF XY:
0.00
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:
0.00000884
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000411
AC:
6
AN:
1461350
Hom.:
0
Cov.:
31
AF XY:
0.00000275
AC XY:
2
AN XY:
727000
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33476
American (AMR)
AF:
0.00
AC:
0
AN:
44712
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:
52980
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000540
AC:
6
AN:
1111946
Other (OTH)
AF:
0.00
AC:
0
AN:
60392
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.492
Heterozygous variant carriers
0
1
2
2
3
4
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:
0.0000197
AC:
3
AN:
152210
Hom.:
0
Cov.:
32
AF XY:
0.0000135
AC XY:
1
AN XY:
74348
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000482
AC:
2
AN:
41452
American (AMR)
AF:
0.00
AC:
0
AN:
15284
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68034
Other (OTH)
AF:
0.000478
AC:
1
AN:
2092
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.0136242), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.392
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:
0.00000824
AC:
1

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Deficiency of alpha-mannosidase Uncertain:3
Jun 07, 2012
ClinVar Staff, National Center for Biotechnology Information (NCBI)
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Jun 03, 2021
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Oct 22, 2021
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Uncertain:1
Aug 20, 2021
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.1501T>A (p.Cys501Ser) results in a non-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 4e-06 in 250324 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1501T>A has been reported in the literature in an individual affected with Type II - Alpha-Mannosidosis. The individual was compound heterozygous for the variant of interest and another pathogenic variant. However, the variant was also in cis with another variant c.2849G>C p.R950P (Borgwardt_2015). Intra cellular processing, transport and secretion studies in cell culture suggested that single mutations p.C501S and p.R950P were processed and transported to lysosomes but in the combined double variant, no indication of lysosomal localization was noted. The authors further report that whether both mutations were required for the disease development remain unknown (Kuokkanen_2011). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.97
BayesDel_addAF
Pathogenic
0.41
D
BayesDel_noAF
Pathogenic
0.35
CADD
Uncertain
25
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.70
D;.
Eigen
Uncertain
0.30
Eigen_PC
Uncertain
0.25
FATHMM_MKL
Uncertain
0.95
D
LIST_S2
Uncertain
0.88
D;D
M_CAP
Uncertain
0.27
D
MetaRNN
Pathogenic
0.97
D;D
MetaSVM
Uncertain
-0.0089
T
MutationAssessor
Uncertain
2.8
M;.
PhyloP100
5.0
PrimateAI
Uncertain
0.58
T
PROVEAN
Pathogenic
-9.8
D;D
REVEL
Pathogenic
0.78
Sift
Uncertain
0.0040
D;D
Sift4G
Uncertain
0.0030
D;D
Polyphen
1.0
D;.
Vest4
0.93
MutPred
0.77
Gain of disorder (P = 0.0084);.;
MVP
0.92
MPC
1.6
ClinPred
1.0
D
GERP RS
5.3
Varity_R
0.79
gMVP
0.95
Mutation Taster
=10/90
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: rs747721968; hg19: chr19-12767789; API