rs753355844

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1PM2PP3_StrongPP5_Very_Strong

The NM_152419.3(HGSNAT):​c.1411G>A​(p.Glu471Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000753 in 1,461,608 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 (★★).

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

HGSNAT
NM_152419.3 missense

Scores

8
7
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 9.46
Variant links:
Genes affected
HGSNAT (HGNC:26527): (heparan-alpha-glucosaminide N-acetyltransferase) This gene encodes a lysosomal acetyltransferase, which is one of several enzymes involved in the lysosomal degradation of heparin sulfate. Mutations in this gene are associated with Sanfilippo syndrome C, one type of the lysosomal storage disease mucopolysaccaridosis III, which results from impaired degradation of heparan sulfate. [provided by RefSeq, Jan 2009]

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 16 ACMG points.

PM1
In a topological_domain Lumenal, vesicle (size 58) in uniprot entity HGNAT_HUMAN there are 9 pathogenic changes around while only 0 benign (100%) in NM_152419.3
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.95
PP5
Variant 8-43193790-G-A is Pathogenic according to our data. Variant chr8-43193790-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 265483.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr8-43193790-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HGSNATNM_152419.3 linkc.1411G>A p.Glu471Lys missense_variant Exon 14 of 18 ENST00000379644.9 NP_689632.2 Q68CP4-2Q8IVU6

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HGSNATENST00000379644.9 linkc.1411G>A p.Glu471Lys missense_variant Exon 14 of 18 2 NM_152419.3 ENSP00000368965.4 Q68CP4-2
HGSNATENST00000521576.1 linkc.562G>A p.Glu188Lys missense_variant Exon 5 of 9 2 ENSP00000429029.1 E5RJN0
HGSNATENST00000524016.5 linkc.514G>A p.Glu172Lys missense_variant Exon 5 of 7 4 ENSP00000428322.1 H0YAZ0
HGSNATENST00000520678.1 linkn.344G>A non_coding_transcript_exon_variant Exon 4 of 4 3

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD3 exomes
AF:
0.0000160
AC:
4
AN:
249268
Hom.:
0
AF XY:
0.0000296
AC XY:
4
AN XY:
135222
show subpopulations
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:
0.0000265
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000753
AC:
11
AN:
1461608
Hom.:
0
Cov.:
30
AF XY:
0.00000963
AC XY:
7
AN XY:
727094
show subpopulations
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:
0.0000232
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000720
Gnomad4 OTH exome
AF:
0.0000166
GnomAD4 genome
Cov.:
33
Alfa
AF:
0.0000363
Hom.:
0
Bravo
AF:
0.0000151
ExAC
AF:
0.00000827
AC:
1

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-C Pathogenic:2
Feb 13, 2017
Counsyl
Significance: Likely pathogenic
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Sep 16, 2020
Natera, Inc.
Significance: Pathogenic
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Mucopolysaccharidosis, MPS-III-C;C4225287:Retinitis pigmentosa 73 Pathogenic:2
Nov 06, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 471 of the HGSNAT protein (p.Glu471Lys). This variant is present in population databases (rs753355844, gnomAD 0.003%). This missense change has been observed in individual(s) with mucopolysaccharidosis type III (PMID: 17033958, 18024218, 19479962). This variant is also known as p.E499K. ClinVar contains an entry for this variant (Variation ID: 265483). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on HGSNAT protein function. Experimental studies have shown that this missense change affects HGSNAT function (PMID: 20583299). For these reasons, this variant has been classified as Pathogenic. -

Oct 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Retinitis pigmentosa 73 Pathogenic:1
Oct 10, 2020
Genetics and Genomic Medicine Centre, NeuroGen Healthcare, NeuroGen Healthcare
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

not provided Pathogenic:1
Dec 14, 2024
GeneDx
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Published functional studies demonstrate the variant causes negligible heparan acetyl CoA: alpha-glucosaminide N-acetyltransferase (HGSNAT) enzyme activity and caused misfolding of the HGSNAT protein and retention in the endoplasmic reticulum (PMID: 20583299, PMID: 19823584); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 17033958, 19823584, 18024218, 19479962, 32770643, 31228227, 31964843, 20583299) -

Sanfilippo syndrome Pathogenic:1
Jun 05, 2017
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant summary: The HGSNAT c.1411G>A (p.Glu471Lys) variant causes the change of "an acidic residue for a basic one just inside the lysosomal luman (Feldhammer_2009)" involving the alteration of a conserved nucleotide and 3/4 in silico tools (SNPsandGO not captured due to low reliability index) predict a damaging outcome for this variant . This variant was found in 1/120760 control chromosomes at a frequency of 0.0000083, which does not exceed the estimated maximal expected allele frequency of a pathogenic HGSNAT variant (0.001). The variant was reported in the literature in MPS type IIIC patients both in the homozygous state and in the compound heterozygous state with other pathogenic variants. Additionally, the variant expressed in various cell model systems was shown to have significantly decreased enzyme activity, and to result in production of misfolded HGSNAT protein that is abnormally glycosylated and not targeted to the lysosome (Fedele_2010, Feldhammer_2009). One clinical diagnostic laboratory classified this variant as pathogenic. Taken together, this variant is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.40
D
BayesDel_noAF
Pathogenic
0.44
CADD
Pathogenic
30
DANN
Pathogenic
1.0
Eigen
Uncertain
0.54
Eigen_PC
Uncertain
0.53
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.97
D;D
M_CAP
Uncertain
0.17
D
MetaRNN
Pathogenic
0.95
D;D
MetaSVM
Uncertain
0.21
D
PrimateAI
Uncertain
0.67
T
PROVEAN
Uncertain
-3.9
D;D
REVEL
Pathogenic
0.92
Sift
Pathogenic
0.0
D;D
Sift4G
Pathogenic
0.0
D;D
Vest4
0.95
MVP
0.89
MPC
0.55
ClinPred
1.0
D
GERP RS
5.1
gMVP
0.99

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.010
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.

Other links and lift over

dbSNP: rs753355844; hg19: chr8-43048933; API