rs1555710357

Positions:

• chr19-12666700-A-G
• chr19-12666700-A-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_000528.4(MAN2B1):​c.2T>C​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000716 in 1,396,502 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: not found (cov: 33)
  • Exomes 𝑓: 7.2e-7 (0 hom.)
• Consequence: MAN2B1 NM_000528.4 start_lost
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.12

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 Pathogenic. Variant got 10 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MAN2B1	NM_000528.4	c.2T>C	p.Met1?	start_lost	1/24	ENST00000456935.7	NP_000519.2
MAN2B1	NM_001173498.2	c.2T>C	p.Met1?	start_lost	1/24		NP_001166969.1
MAN2B1	XM_005259913.3	c.2T>C	p.Met1?	start_lost	1/24		XP_005259970.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MAN2B1	ENST00000456935.7	c.2T>C	p.Met1?	start_lost	1/24	1	NM_000528.4	ENSP00000395473	A1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.16e-7 AC: 1 AN: 1396502 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 688790

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: 9.27e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Deficiency of alpha-mannosidase Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Apr 27, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Apr 03, 2018	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.20
CADD	Benign	19
DANN	Benign	0.97
DEOGEN2	Benign	0.14	T;.;.;.
Eigen	Benign	0.12
Eigen_PC	Benign	0.11
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.90	D;D;D;D
M_CAP	Pathogenic	0.67	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Uncertain	-0.14	T
MutationTaster	Benign	0.99	D;D
PROVEAN	Benign	-1.5	N;N;.;.
REVEL	Uncertain	0.54
Sift	Pathogenic	0.0	D;D;.;.
Sift4G	Pathogenic	0.0	D;D;.;D
Polyphen		0.68	P;.;.;.
Vest4		0.92
MutPred		1.0		Loss of MoRF binding (P = 0.0686);Loss of MoRF binding (P = 0.0686);Loss of MoRF binding (P = 0.0686);Loss of MoRF binding (P = 0.0686);
MVP		0.91
ClinPred		0.75	D
GERP RS		4.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.96
gMVP		0.88

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

LitVar

Other links and lift over

dbSNP: rs1555710357; hg19: chr19-12777514;