19-12646654-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000528.4(MAN2B1):c.3002T>C(p.Leu1001Pro) variant causes a missense change. The variant allele was found at a frequency of 0.0000297 in 1,613,908 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 (★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 31)
  • Exomes 𝑓: 0.000031 (0 hom.)
• Consequence: MAN2B1 NM_000528.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.97

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.908

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MAN2B1	NM_000528.4	c.3002T>C	p.Leu1001Pro	missense_variant	24/24	ENST00000456935.7
MAN2B1	NM_001173498.2	c.2999T>C	p.Leu1000Pro	missense_variant	24/24
MAN2B1	XM_005259913.3	c.3005T>C	p.Leu1002Pro	missense_variant	24/24
MAN2B1	XM_047438841.1	c.1901T>C	p.Leu634Pro	missense_variant	17/17

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MAN2B1	ENST00000456935.7	c.3002T>C	p.Leu1001Pro	missense_variant	24/24	1	NM_000528.4	A1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152112 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

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

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251484 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135918

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: 0.00

Gnomad NFE exome AF: 0.0000352

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000315 AC: 46 AN: 1461796 Hom.: 0 Cov.: 31 AF XY: 0.0000303 AC XY: 22 AN XY: 727208

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: 0.00

Gnomad4 NFE exome AF: 0.0000387

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152112 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 74296

Gnomad4 AFR AF: 0.00

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: 0.0000294

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000151

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Deficiency of alpha-mannosidase Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 18, 2022

This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 1001 of the MAN2B1 protein (p.Leu1001Pro). This variant is present in population databases (rs762104115, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with MAN2B1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Pathogenic	0.24
Cadd	Pathogenic	27
Dann	Pathogenic	1.0
DEOGEN2	Pathogenic	0.83	D;.
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.80	T;T
M_CAP	Uncertain	0.17	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.48	D
MutationAssessor	Pathogenic	3.2	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.43	T
PROVEAN	Uncertain	-3.6	D;D
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0040	D;D
Sift4G	Uncertain	0.023	D;D
Polyphen		1.0	D;.
Vest4		0.82
MutPred		0.72		Gain of sheet (P = 0.0266);.;
MVP		0.98
MPC		1.1
ClinPred		0.86	D
GERP RS		5.9
Varity_R		0.96
gMVP		0.93

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

LitVar

Other links and lift over

dbSNP: rs762104115; hg19: chr19-12757468;