4-102631885-C-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BS1_Supporting

The NM_005908.4(MANBA):c.*172G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000219 in 675,644 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00016 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00024 (1 hom.)
• Consequence: MANBA NM_005908.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.215

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_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.69).
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000164 (25/152344) while in subpopulation EAS AF= 0.00328 (17/5190). AF 95% confidence interval is 0.00209. There are 0 homozygotes in gnomad4. There are 11 alleles in male gnomad4 subpopulation. Median coverage is 32. 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/exons	MANE	UniProt
MANBA	NM_005908.4	c.*172G>A		3_prime_UTR_variant	17/17	ENST00000647097.2
MANBA	XM_047415692.1	c.*172G>A		3_prime_UTR_variant	18/18
MANBA	XM_047415693.1	c.*172G>A		3_prime_UTR_variant	18/18
MANBA	XM_047415694.1	c.*172G>A		3_prime_UTR_variant	13/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MANBA	ENST00000647097.2	c.*172G>A		3_prime_UTR_variant	17/17		NM_005908.4	P1

Frequencies

GnomAD3 genomes AF: 0.000164 AC: 25 AN: 152226 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00327

Gnomad SAS AF: 0.00124

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.000479

GnomAD4 exome AF: 0.000235 AC: 123 AN: 523300 Hom.: 1 Cov.: 5 AF XY: 0.000247 AC XY: 69 AN XY: 279280

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000333

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00304

Gnomad4 SAS exome AF: 0.000353

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000320

Gnomad4 OTH exome AF: 0.000172

GnomAD4 genome AF: 0.000164 AC: 25 AN: 152344 Hom.: 0 Cov.: 32 AF XY: 0.000148 AC XY: 11 AN XY: 74518

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00328

Gnomad4 SAS AF: 0.00124

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.000474

Bravo AF: 0.000204

Asia WGS AF: 0.000577 AC: 2 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Beta-D-mannosidosis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 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	-0.69
Cadd	Benign	8.0
Dann	Benign	0.86

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs146374185; hg19: chr4-103553042;