Genetic Variant MAN1B1:p.His259Leu (chr9-137099741-A-T) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

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

The NM_016219.5(MAN1B1):c.776A>T(p.His259Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,850 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H259R) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MAN1B1
NM_016219.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.07

Publications

0 publications found

Variant links:

Genes affected

MAN1B1 (HGNC:6823): (mannosidase alpha class 1B member 1) This gene encodes an enzyme belonging to the glycosyl hydrolase 47 family. This enzyme functions in N-glycan biosynthesis, and is a class I alpha-1,2-mannosidase that specifically converts Man9GlcNAc to Man8GlcNAc isomer B. It is required for N-glycan trimming to Man5-6GlcNAc2 in the endoplasmic-reticulum-associated degradation pathway. Mutations in this gene cause autosomal-recessive intellectual disability. Alternative splicing results in multiple transcript variants. A related pseudogene has been identified on chromosome 11. [provided by RefSeq, Dec 2011]

MAN1B1 Gene-Disease associations (from GenCC):

MAN1B1-congenital disorder of glycosylation
Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
Rafiq syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae), Ambry Genetics
autosomal recessive non-syndromic intellectual disability
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

MAN1B1 links:

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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, 0.956

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
MAN1B1	NM_016219.5 link	c.776A>T	p.His259Leu	missense_variant	Exon 6 of 13	ENST00000371589.9	NP_057303.2
MAN1B1	XM_006716945.5 link	c.776A>T	p.His259Leu	missense_variant	Exon 6 of 12		XP_006717008.1
MAN1B1	NR_045720.2 link	n.791A>T		non_coding_transcript_exon_variant	Exon 6 of 13
MAN1B1	NR_045721.2 link	n.922A>T		non_coding_transcript_exon_variant	Exon 7 of 14

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MAN1B1	ENST00000371589.9 link	c.776A>T	p.His259Leu	missense_variant	Exon 6 of 13	1	NM_016219.5	ENSP00000360645.4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461850

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727224

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53380

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.55

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Uncertain

0.070

CADD

Uncertain

(source)

DANN

Benign

0.96

DEOGEN2

Uncertain

0.64

D;D

Eigen

Uncertain

0.55

Eigen_PC

Uncertain

0.40

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.86

D;D

M_CAP

Pathogenic

0.40

MetaRNN

Pathogenic

0.96

D;D

MetaSVM

Uncertain

0.36

MutationAssessor

Uncertain

2.5

M;.

PhyloP100

9.1

PrimateAI

Uncertain

0.66

PROVEAN

Pathogenic

-10

D;.

REVEL

Pathogenic

0.67

Sift

Benign

0.23

T;.

Sift4G

Uncertain

0.048

D;D

Polyphen

1.0

D;.

Vest4

0.91

MutPred

0.71

Loss of methylation at K262 (P = 0.0666);.;

MVP

0.93

MPC

0.48

ClinPred

1.0

GERP RS

4.7

Varity_R

0.79

gMVP

0.92

Mutation Taster

=134/166

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.18

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over