19-12646579-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000528.4(MAN2B1):c.*41C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000389 in 1,459,372 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 0.00018 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00041 (0 hom.)
• Consequence: MAN2B1 NM_000528.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -2.60

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 Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MAN2B1	NM_000528.4	c.*41C>T		3_prime_UTR_variant	24/24	ENST00000456935.7
MAN2B1	NM_001173498.2	c.*41C>T		3_prime_UTR_variant	24/24
MAN2B1	XM_005259913.3	c.*41C>T		3_prime_UTR_variant	24/24
MAN2B1	XM_047438841.1	c.*41C>T		3_prime_UTR_variant	17/17

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MAN2B1	ENST00000456935.7	c.*41C>T		3_prime_UTR_variant	24/24	1	NM_000528.4	A1

Frequencies

GnomAD3 genomes AF: 0.000184 AC: 28 AN: 152174 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000145

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.000188

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000279

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000180 AC: 45 AN: 249440 Hom.: 0 AF XY: 0.000141 AC XY: 19 AN XY: 134928

Gnomad AFR exome AF: 0.000124

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000164

Gnomad SAS exome AF: 0.0000328

Gnomad FIN exome AF: 0.0000933

Gnomad NFE exome AF: 0.000320

Gnomad OTH exome AF: 0.000164

GnomAD4 exome AF: 0.000412 AC: 539 AN: 1307198 Hom.: 0 Cov.: 21 AF XY: 0.000394 AC XY: 259 AN XY: 658140

Gnomad4 AFR exome AF: 0.0000662

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000770

Gnomad4 SAS exome AF: 0.0000120

Gnomad4 FIN exome AF: 0.000150

Gnomad4 NFE exome AF: 0.000511

Gnomad4 OTH exome AF: 0.000524

GnomAD4 genome AF: 0.000184 AC: 28 AN: 152174 Hom.: 0 Cov.: 32 AF XY: 0.000148 AC XY: 11 AN XY: 74340

Gnomad4 AFR AF: 0.000145

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.000188

Gnomad4 NFE AF: 0.000279

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000215 Hom.: 0

Bravo AF: 0.000223

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

Illumina Laboratory Services, Illumina

Jan 15, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
Cadd	Benign	0.095
Dann	Benign	0.47
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs371716069; hg19: chr19-12757393;