chr19-12647233-CT-C

Variant names:

• chr19-12647233-CT-C
• rs1057516897
• NM_000528.4:c.2922delA

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PVS1_Strong PM2 PP5

The NM_000528.4(MAN2B1):​c.2922delA​(p.Gly975AlafsTer58) variant causes a frameshift, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MAN2B1 NM_000528.4 frameshift, splice_region
• Clinical Significance: Likely pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: -2.53
• Publications: 0 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)

ENSG00000269242 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 6 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 19-12647233-CT-C is Pathogenic according to our data. Variant chr19-12647233-CT-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 370959.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MAN2B1	NM_000528.4	c.2922delA	p.Gly975AlafsTer58	frameshift_variant, splice_region_variant	Exon 23 of 24	ENST00000456935.7	NP_000519.2
MAN2B1	NM_001440570.1	c.2925delA	p.Gly976AlafsTer58	frameshift_variant, splice_region_variant	Exon 23 of 24		NP_001427499.1
MAN2B1	NM_001173498.2	c.2919delA	p.Gly974AlafsTer58	frameshift_variant, splice_region_variant	Exon 23 of 24		NP_001166969.1
MAN2B1	XM_047438841.1	c.1821delA	p.Gly608AlafsTer58	frameshift_variant, splice_region_variant	Exon 16 of 17		XP_047294797.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MAN2B1	ENST00000456935.7	c.2922delA	p.Gly975AlafsTer58	frameshift_variant, splice_region_variant	Exon 23 of 24	1	NM_000528.4	ENSP00000395473.2
ENSG00000269242	ENST00000597692.1	n.480delA		splice_region_variant, non_coding_transcript_exon_variant	Exon 3 of 5	2		ENSP00000470240.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Deficiency of alpha-mannosidase Pathogenic:1

May 27, 2016

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-2.5

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.25		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.25		Position offset: -18

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

Other links and lift over

dbSNP: rs1057516897; hg19: chr19-12758047;