19-12655693-C-G

Position:

chr19-12655693-C-G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_ModeratePM2PP5_Very_Strong

The NM_000528.4(MAN2B1):c.1830+1G>C variant causes a splice donor change. The variant allele was found at a frequency of 0.000167 in 1,608,824 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

Frequency

Genomes: 𝑓 0.000079 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00018 ( 0 hom. )

Consequence

MAN2B1
NM_000528.4 splice_donor

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:14O:1

Conservation

PhyloP100: 5.67

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.06093544 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 19-12655693-C-G is Pathogenic according to our data. Variant chr19-12655693-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 21207.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr19-12655693-C-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	MANE	Protein
MAN2B1	NM_000528.4 linkuse as main transcript	c.1830+1G>C	splice_donor_variant	ENST00000456935.7	NP_000519.2
MAN2B1	NM_001173498.2 linkuse as main transcript	c.1827+1G>C	splice_donor_variant		NP_001166969.1
MAN2B1	XM_005259913.3 linkuse as main transcript	c.1833+1G>C	splice_donor_variant		XP_005259970.1
MAN2B1	XM_047438841.1 linkuse as main transcript	c.729+1G>C	splice_donor_variant		XP_047294797.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MAN2B1	ENST00000456935.7 linkuse as main transcript	c.1830+1G>C		splice_donor_variant		1	NM_000528.4	ENSP00000395473	A1	O00754-1

Frequencies

GnomAD3 genomes

AF:

0.0000789

AC:

AN:

152118

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.000162

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000925

AC:

AN:

248630

Hom.:

AF XY:

0.000104

AC XY:

AN XY:

134398

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000326

Gnomad NFE exome

AF:

0.000142

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000176

AC:

257

AN:

1456706

Hom.:

Cov.:

AF XY:

0.000152

AC XY:

110

AN XY:

723972

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.000413

Gnomad4 NFE exome

AF:

0.000204

Gnomad4 OTH exome

AF:

0.000150

GnomAD4 genome

AF:

0.0000789

AC:

AN:

152118

Hom.:

Cov.:

AF XY:

0.0000942

AC XY:

AN XY:

74284

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000162

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000135

Hom.:

Bravo

AF:

0.0000756

ExAC

AF:

0.0000659

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:14Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Deficiency of alpha-mannosidase

Pathogenic:12Other:1

Pathogenic, no assertion criteria provided	literature only	OMIM	Mar 01, 2012	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 25, 2019	Variant summary: MAN2B1 c.1830+1G>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 9.3e-05 in 248630 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in MAN2B1 causing Alpha-Mannosidosis (9.3e-05 vs 0.0016). c.1830+1G>C has been reported in the literature as one of the most common disease causing variants in multiple individuals affected with Alpha-Mannosidosis (example, Riise Stensland_2012, Berg_1999). These data indicate that the variant is very likely to be associated with disease. No experimental evidence demonstrating an impact on protein function were ascertained within the context of this evaluation. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Oct 01, 2021	NM_000528.3(MAN2B1):c.1830+1G>C is a canonical splice variant classified as pathogenic in the context of alpha-mannosidosis. c.1830+1G>C has been observed in cases with relevant disease (PMID: 9915946, 22161967). Functional assessments of this variant are not available in the literature. c.1830+1G>C has been observed in population frequency databases (gnomAD: FIN 0.03%). In summary, NM_000528.3(MAN2B1):c.1830+1G>C is a canonical splice variant that has been observed more frequently in cases with the relevant disease than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -
not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	May 26, 2020	Based on the classification scheme VCGS_Germline_v1.1.1, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss-of-function is a known mechanism of disease for this gene. (N) 0106 - This gene is known to be associated with autosomal recessive disease. (N) 0211 - Canonical splice site variant without proven consequence on splicing (no functional evidence available, intron 14). (P) 0251 - Variant is heterozygous. (N) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (24 heterozygotes, 0 homozygotes). (P) 0505 - Abnormal splicing is predicted by in silico tools and affected nucleotide is highly conserved. (P) 0704 - Comparable variant has low previous evidence for pathogenicity (Borgwardt, L. et al. (2015); Riise Stensland, H. et al. (2012)). (P) 0801 - Strong previous evidence of pathogenicity in unrelated individuals (ClinVar; Matlach, J. et al (2018)). (P) 1102 - Strong phenotype match. (P) 1205 - Variant is maternally inherited. (N) Legend: (P) - Pathogenic, (N) - Neutral, (B) - Benign -
Pathogenic, criteria provided, single submitter	clinical testing	Greenwood Genetic Center Diagnostic Laboratories, Greenwood Genetic Center	Feb 02, 2022	PVS1, PM2, PM3 -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 29, 2024	This sequence change affects a donor splice site in intron 14 of the MAN2B1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in MAN2B1 are known to be pathogenic (PMID: 9915946, 22161967). This variant is present in population databases (rs80338677, gnomAD 0.03%). Disruption of this splice site has been observed in individual(s) with mannosidosis (PMID: 9915946, 26048034). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as IVS14+1G>C. ClinVar contains an entry for this variant (Variation ID: 21207). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 15, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	May 22, 2020	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 05, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	New York Genome Center	Apr 09, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Nov 17, 2021	- -

Inborn genetic diseases

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 20, 2017

- -

not provided

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Sep 20, 2024

Canonical splice site variant predicted to result in an in-frame loss of the adjacent exon in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 25525159, 9915946, 22161967, 31980526, 34429528, 38382588, 38107468) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.46

BayesDel_noAF

Pathogenic

0.17

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

0.92

Eigen_PC

Pathogenic

0.71

FATHMM_MKL

Pathogenic

0.97

MutationTaster

Benign

1.0

A;A

GERP RS

3.5

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.95

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.95

Position offset: 1

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