rs864621987

Variant names:

• chr19-12649946-G-C
• rs864621987
• NM_000528.4:c.2234C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000528.4(MAN2B1):​c.2234C>G​(p.Thr745Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (no stars).

• Frequency: Genomes: not found (cov: 30)
• Consequence: MAN2B1 NM_000528.4 missense
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 8.93
• Publications: 4 publications found

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)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 uncertain in NM_000528.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.952

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000528.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MAN2B1	NM_000528.4	MANE Select	c.2234C>G	p.Thr745Arg	missense	Exon 18 of 24	NP_000519.2
	MAN2B1	NM_001440570.1		c.2237C>G	p.Thr746Arg	missense	Exon 18 of 24	NP_001427499.1
	MAN2B1	NM_001173498.2		c.2231C>G	p.Thr744Arg	missense	Exon 18 of 24	NP_001166969.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MAN2B1	ENST00000456935.7	TSL:1 MANE Select	c.2234C>G	p.Thr745Arg	missense	Exon 18 of 24	ENSP00000395473.2
	MAN2B1	ENST00000221363.9	TSL:1	c.2231C>G	p.Thr744Arg	missense	Exon 18 of 24	ENSP00000221363.4
	MAN2B1	ENST00000466794.5	TSL:2	n.2824C>G		non_coding_transcript_exon	Exon 16 of 22

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 30

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
-	1	-	Deficiency of alpha-mannosidase (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.91	D
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.84	T
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.2	M
PhyloP100		8.9
PrimateAI	Uncertain	0.52	T
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.91
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.69		Loss of phosphorylation at T745 (P = 0.017)
MVP		0.98
MPC		0.89
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.97
gMVP		0.95
Mutation Taster		=1/99	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

Other links and lift over

dbSNP: rs864621987; hg19: chr19-12760760;