rs1060499680

Positions:

• chr12-101768036-C-A
• chr12-101768036-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_024312.5(GNPTAB):​c.1408+1G>T variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,738 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GNPTAB NM_024312.5 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.29

Genes affected

GNPTAB (HGNC:29670): (N-acetylglucosamine-1-phosphate transferase subunits alpha and beta) This gene encodes two of three subunit types of the membrane-bound enzyme N-acetylglucosamine-1-phosphotransferase, a heterohexameric complex composed of two alpha, two beta, and two gamma subunits. The encoded protein is proteolytically cleaved at the Lys928-Asp929 bond to yield mature alpha and beta polypeptides while the gamma subunits are the product of a distinct gene (GeneID 84572). In the Golgi apparatus, the heterohexameric complex catalyzes the first step in the synthesis of mannose 6-phosphate recognition markers on certain oligosaccharides of newly synthesized lysosomal enzymes. These recognition markers are essential for appropriate trafficking of lysosomal enzymes. Mutations in this gene have been associated with both mucolipidosis II and mucolipidosis IIIA.[provided by RefSeq, May 2010]

GNPTAB (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-101768036-C-A is Pathogenic according to our data. Variant chr12-101768036-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 397559.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GNPTAB	NM_024312.5	c.1408+1G>T		splice_donor_variant, intron_variant		ENST00000299314.12	NP_077288.2
GNPTAB	XM_011538731.3	c.1327+1G>T		splice_donor_variant, intron_variant			XP_011537033.1
GNPTAB	XM_006719593.4	c.1408+1G>T		splice_donor_variant, intron_variant			XP_006719656.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GNPTAB	ENST00000549940.5	c.1409G>T	p.Gly470Val	missense_variant	11/11	1		ENSP00000449150.1
GNPTAB	ENST00000299314.12	c.1408+1G>T		splice_donor_variant, intron_variant		1	NM_024312.5	ENSP00000299314.7
GNPTAB	ENST00000552009.1	n.67+1G>T		splice_donor_variant, intron_variant		3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461738 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727192

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Pseudo-Hurler polydystrophy;C2673377:Mucolipidosis type II Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 06, 2023	This sequence change affects a donor splice site in intron 11 of the GNPTAB gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in GNPTAB are known to be pathogenic (PMID: 19617216, 25107912). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with GNPTAB-related conditions (PMID: 32651481). ClinVar contains an entry for this variant (Variation ID: 397559). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	research	Diagnostics Division, CENTRE FOR DNA FINGERPRINTING AND DIAGNOSTICS	Jan 01, 2016	- -

Mucolipidosis type II Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics

Apr 20, 2021

A homozygous 3’ splice site variation in intron 11 of the GNPTAB gene that affects the invariant AG acceptor splice site upstream of exon 12 was detected. The observed variant c.1408+1G>T has not been reported in the 1000 genomes and gnomAD databases. The in silico prediction of the variant is damaging by MutationTaster, DANN and FATHMM. In summary, the variant meets our criteria to be classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Pathogenic	0.32	D
ClinPred		0.98	D
GERP RS		5.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.91
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.99		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1060499680; hg19: chr12-102161814;