rs1341763493

Variant names:

• chr4-102634846-TTGGTC-T
• rs1341763493
• NM_005908.4:c.2352_2356delGACCA

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_005908.4(MANBA):​c.2352_2356delGACCA​(p.Thr785LeufsTer27) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000116 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: MANBA NM_005908.4 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.58

Genes affected

MANBA (HGNC:6831): (mannosidase beta) This gene encodes a member of the glycosyl hydrolase 2 family. The encoded protein localizes to the lysosome where it is the final exoglycosidase in the pathway for N-linked glycoprotein oligosaccharide catabolism. Mutations in this gene are associated with beta-mannosidosis, a lysosomal storage disease that has a wide spectrum of neurological involvement. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 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. Fraction of 0.109 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-102634846-TTGGTC-T is Pathogenic according to our data. Variant chr4-102634846-TTGGTC-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 542165.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MANBA	NM_005908.4	c.2352_2356delGACCA	p.Thr785LeufsTer27	frameshift_variant	Exon 16 of 17	ENST00000647097.2	NP_005899.3
MANBA	XM_047415692.1	c.2277_2281delGACCA	p.Thr760LeufsTer27	frameshift_variant	Exon 17 of 18		XP_047271648.1
MANBA	XM_047415693.1	c.2277_2281delGACCA	p.Thr760LeufsTer27	frameshift_variant	Exon 17 of 18		XP_047271649.1
MANBA	XM_047415694.1	c.1704_1708delGACCA	p.Thr569LeufsTer27	frameshift_variant	Exon 12 of 13		XP_047271650.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MANBA	ENST00000647097.2	c.2352_2356delGACCA	p.Thr785LeufsTer27	frameshift_variant	Exon 16 of 17		NM_005908.4	ENSP00000495247.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251414 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135870

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000116 AC: 17 AN: 1461874 Hom.: 0 AF XY: 0.0000151 AC XY: 11 AN XY: 727238

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000144

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Beta-D-mannosidosis Pathogenic:1

Feb 23, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Thr785Leufs*27) in the MANBA gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 95 amino acid(s) of the MANBA protein. This variant is present in population databases (no rsID available, gnomAD 0.002%). This premature translational stop signal has been observed in individual(s) with mannosidosis (Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 542165). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs1341763493; hg19: chr4-103556003;