chr9-137108482-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 3P and 3B. PM2PP3BP4_ModerateBS1_Supporting

The NM_016219.5(MAN1B1):c.1991C>T(p.Thr664Met) variant causes a missense change. The variant allele was found at a frequency of 0.000129 in 1,613,878 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.00032 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00011 ( 0 hom. )

Consequence

MAN1B1
NM_016219.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: 4.52

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Multiple lines of computational evidence support a deleterious effect 8: BayesDel_noAF, Cadd, Dann, Eigen, M_CAP, MutationAssessor, PROVEAN, REVEL [when max_spliceai, FATHMM_MKL, MetaRNN, MutationTaster was below the threshold]

BP4

Computational evidence support a benign effect (MetaRNN=0.07513967).

BS1

Variant frequency is greater than expected in population amr. gnomad4 allele frequency = 0.000315 (48/152310) while in subpopulation AMR AF= 0.00261 (40/15298). AF 95% confidence interval is 0.00197. There are 0 homozygotes in gnomad4. There are 19 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MAN1B1	NM_016219.5 link	c.1991C>T	p.Thr664Met	missense_variant	Exon 13 of 13	ENST00000371589.9	NP_057303.2	Q9UKM7
MAN1B1	NR_045720.2 link	n.1981C>T		non_coding_transcript_exon_variant	Exon 13 of 13
MAN1B1	NR_045721.2 link	n.2137C>T		non_coding_transcript_exon_variant	Exon 14 of 14
MAN1B1	XM_006716945.5 link	c.*520C>T		downstream_gene_variant			XP_006717008.1	H0YG20

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MAN1B1	ENST00000371589.9 link	c.1991C>T	p.Thr664Met	missense_variant	Exon 13 of 13	1	NM_016219.5	ENSP00000360645.4		Q9UKM7

Frequencies

GnomAD3 genomes

AF:

0.000309

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00255

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.000957

GnomAD3 exomes

AF:

0.000239

AC:

AN:

251474

Hom.:

AF XY:

0.000177

AC XY:

AN XY:

135914

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00136

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.0000653

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00114

GnomAD4 exome

AF:

0.000109

AC:

160

AN:

1461568

Hom.:

Cov.:

AF XY:

0.000105

AC XY:

AN XY:

727102

show subpopulations

Gnomad4 AFR exome

AF:

0.0000896

Gnomad4 AMR exome

AF:

0.00226

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000696

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000306

Gnomad4 OTH exome

AF:

0.000248

GnomAD4 genome

AF:

0.000315

AC:

AN:

152310

Hom.:

Cov.:

AF XY:

0.000255

AC XY:

AN XY:

74472

show subpopulations

Gnomad4 AFR

AF:

0.0000481

Gnomad4 AMR

AF:

0.00261

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.000947

Alfa

AF:

0.0000814

Hom.:

Bravo

AF:

0.000314

ExAC

AF:

0.000157

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Rafiq syndrome

Uncertain:3

Jan 08, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 664 of the MAN1B1 protein (p.Thr664Met). This variant is present in population databases (rs200428790, gnomAD 0.1%). This variant has not been reported in the literature in individuals affected with MAN1B1-related conditions. ClinVar contains an entry for this variant (Variation ID: 435811). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -

May 20, 2024

Pittsburgh Clinical Genomics Laboratory, University of Pittsburgh Medical Center

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence variant is a single nucleotide substitution (C>T) at position 1991 of the coding sequence of the MAN1B1 gene that results in a threonine to methionine amino acid change at residue 664 of the mannosidase alpha class 1B member 1 protein. This is a previously reported variant (ClinVar 435811) that has not been observed in individuals affected by MAN1B1-related disorder in the published literature, to our knowledge. This variant is present in 208 of 1613878 alleles (0.013%) in the gnomAD v4.1.0 population dataset. Multiple bioinformatic tools predict that this amino acid change would be damaging, and the Thr664 residue at this position is highly conserved across the vertebrate species examined. Studies examining the functional consequence of this variant have not been published, to our knowledge. At this time, there is insufficient evidence to determine if this variant is pathogenic or benign. Therefore, we consider this a variant of uncertain significance. ACMG Criteria: PP3 -

Jun 17, 2021

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Uncertain:2

Aug 28, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Identified by whole exome sequencing in the heterozygous state in an individual with intellectual disability who was also homozygous for a likely pathogenic PEX16 variant (PMID: 26870756); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 26870756) -

Jul 09, 2020

AiLife Diagnostics, AiLife Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified

Uncertain:1

Aug 18, 2015

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases

Uncertain:1

Dec 18, 2017

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T664M variant (also known as c.1991C>T), located in coding exon 13 of the MAN1B1 gene, results from a C to T substitution at nucleotide position 1991. The threonine at codon 664 is replaced by methionine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.56

BayesDel_addAF

Uncertain

0.083

BayesDel_noAF

Pathogenic

0.35

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.81

Eigen

Pathogenic

0.83

Eigen_PC

Pathogenic

0.75

FATHMM_MKL

Uncertain

0.90

LIST_S2

Pathogenic

0.99

M_CAP

Pathogenic

0.56

MetaRNN

Benign

0.075

MetaSVM

Uncertain

0.70

MutationAssessor

Pathogenic

4.4

PrimateAI

Uncertain

0.64

PROVEAN

Pathogenic

-5.5

REVEL

Pathogenic

0.90

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.50

MVP

0.97

MPC

0.45

ClinPred

0.51

GERP RS

5.4

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.84

gMVP

0.89

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

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