16-1351972-G-A

Position:

chr16-1351972-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 4P and 3B. PM2PM5BP4_ModerateBS1_Supporting

The NM_032520.5(GNPTG):c.7G>A(p.Ala3Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000107 in 1,317,162 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A3V) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.00049 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000057 ( 0 hom. )

Consequence

GNPTG
NM_032520.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:2

Conservation

PhyloP100: 2.82

Variant links:

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]

GNPTG links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr16-1351973-C-T is described in Lovd as [Likely_pathogenic].

BP4

Computational evidence support a benign effect (MetaRNN=0.25590178).

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000494 (75/151778) while in subpopulation AFR AF= 0.00159 (66/41516). AF 95% confidence interval is 0.00128. There are 0 homozygotes in gnomad4. There are 38 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	Protein	UniProt
GNPTG	NM_032520.5 linkuse as main transcript	c.7G>A	p.Ala3Thr	missense_variant	1/11	ENST00000204679.9	NP_115909.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GNPTG	ENST00000204679.9 linkuse as main transcript	c.7G>A	p.Ala3Thr	missense_variant	1/11	1	NM_032520.5	ENSP00000204679	P1

Frequencies

GnomAD3 genomes

AF:

0.000488

AC:

AN:

151670

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00157

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000197

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:

0.0000884

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000566

AC:

AN:

1165384

Hom.:

Cov.:

AF XY:

0.0000603

AC XY:

AN XY:

564232

show subpopulations

Gnomad4 AFR exome

AF:

0.00243

Gnomad4 AMR exome

AF:

0.000262

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.000127

GnomAD4 genome

AF:

0.000494

AC:

AN:

151778

Hom.:

Cov.:

AF XY:

0.000512

AC XY:

AN XY:

74196

show subpopulations

Gnomad4 AFR

AF:

0.00159

Gnomad4 AMR

AF:

0.000197

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000885

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000427

Hom.:

Bravo

AF:

0.000642

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

GNPTG-mucolipidosis

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Oct 31, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Feb 01, 2017	- -

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 13, 2022	This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 3 of the GNPTG protein (p.Ala3Thr). This variant is present in population databases (no rsID available, gnomAD 0.1%). This variant has not been reported in the literature in individuals affected with GNPTG-related conditions. ClinVar contains an entry for this variant (Variation ID: 550565). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -

not specified

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Aug 02, 2024

Variant summary: GNPTG c.7G>A (p.Ala3Thr) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00011 in 1317162 control chromosomes, predominantly at a frequency of 0.0019 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 1.075 fold of the estimated maximal expected allele frequency for a pathogenic variant in GNPTG causing Mucolipidosis III Gamma phenotype (0.0018). To our knowledge, no occurrence of c.7G>A in individuals affected with Mucolipidosis III Gamma and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 550565). Based on the evidence outlined above, the variant was classified as likely benign. -

GNPTG-related disorder

Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 08, 2023

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.24

BayesDel_noAF

Benign

-0.15

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.18

T;.

Eigen

Benign

-0.23

Eigen_PC

Benign

-0.21

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.36

T;T

M_CAP

Pathogenic

0.98

MetaRNN

Benign

0.26

T;T

MetaSVM

Benign

-0.41

MutationAssessor

Uncertain

2.1

M;.

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.66

PROVEAN

Benign

-0.44

N;.

REVEL

Benign

0.20

Sift

Benign

0.11

T;.

Sift4G

Uncertain

0.043

D;D

Polyphen

0.42

B;.

Vest4

0.23

MVP

0.94

MPC

0.0067

ClinPred

0.44

GERP RS

2.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

2.0

Varity_R

0.091

gMVP

0.62

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over