rs193302848

chr16-1361760-C-T

Variant summary

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

The NM_032520.5(GNPTG):c.196C>T(p.Arg66Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000867 in 1,613,978 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R66R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: GNPTG NM_032520.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5 O:1
• Conservation: PhyloP100: 1.57

Genes affected

GNPTG (HGNC:23026): (N-acetylglucosamine-1-phosphate transferase subunit gamma) This gene encodes the gamma sunbunit of the N-acetylglucosamine-1-phosphotransferase complex. This hexameric complex, composed of alpha, beta and gamma subunits, catalyzes the first step in synthesis of a mannose 6-phosphate lysosomal recognition marker. This enzyme complex is necessary for targeting of lysosomal hydrolases to the lysosome. Mutations in the gene encoding the gamma subunit have been associated with mucolipidosis IIIC, also known as mucolipidosis III gamma.[provided by RefSeq, Feb 2010]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-1361760-C-T is Pathogenic according to our data. Variant chr16-1361760-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 21713.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr16-1361760-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GNPTG	NM_032520.5	c.196C>T	p.Arg66Ter	stop_gained	4/11	ENST00000204679.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GNPTG	ENST00000204679.9	c.196C>T	p.Arg66Ter	stop_gained	4/11	1	NM_032520.5	P1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152142 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

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: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251264 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135846

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: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461836 Hom.: 0 Cov.: 32 AF XY: 0.0000110 AC XY: 8 AN XY: 727214

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: 0.00000989

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152142 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74310

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000278 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

GNPTG-mucolipidosis Pathogenic:3 Other:1

not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	Sep 21, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Oct 17, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Oct 17, 2023	This sequence change creates a premature translational stop signal (p.Arg66*) in the GNPTG gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in GNPTG are known to be pathogenic (PMID: 19370764, 20301784). This variant is present in population databases (rs193302848, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with mucolipidosis type III gamma (PMID: 15060128, 28950892). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 21713). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Uncertain	0.10
Cadd	Pathogenic	35
Dann	Benign	0.89
Eigen	Benign	-0.42
Eigen_PC	Benign	-0.77
FATHMM_MKL	Benign	0.28	N
MutationTaster	Benign	1.0	A
Vest4		0.81
ClinPred		0.78	D
GERP RS		-1.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs193302848; hg19: chr16-1411761; COSMIC: COSV50190382; COSMIC: COSV50190382;