Genetic Variant NM_152419.3:c.1345dupG (chr8-43192397-A-AG) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_152419.3(HGSNAT):c.1345dupG(p.Asp449GlyfsTer21) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000267 in 1,461,156 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.000027 ( 0 hom. )

Consequence

HGSNAT
NM_152419.3 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 5.14

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]

HGSNAT links:

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ACMG classification

Classification made for transcript

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 8-43192397-A-AG is Pathogenic according to our data. Variant chr8-43192397-A-AG is described in ClinVar as [Pathogenic]. Clinvar id is 1231.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HGSNAT	NM_152419.3 link	c.1345dupG	p.Asp449GlyfsTer21	frameshift_variant	Exon 13 of 18	ENST00000379644.9	NP_689632.2	Q68CP4-2Q8IVU6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
HGSNAT	ENST00000379644.9 link	c.1345dupG	p.Asp449GlyfsTer21	frameshift_variant	Exon 13 of 18	2	NM_152419.3	ENSP00000368965.4	Q68CP4-2
HGSNAT	ENST00000521576.1 link	c.496dupG	p.Asp166GlyfsTer21	frameshift_variant	Exon 4 of 9	2		ENSP00000429029.1	E5RJN0
HGSNAT	ENST00000524016.5 link	c.448dupG	p.Asp150fs	frameshift_variant	Exon 4 of 7	4		ENSP00000428322.1	H0YAZ0
HGSNAT	ENST00000520678.1 link	n.278dupG		non_coding_transcript_exon_variant	Exon 3 of 4	3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000806

AC:

AN:

248232

Hom.:

AF XY:

0.0000148

AC XY:

AN XY:

134684

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:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000887

Gnomad OTH exome

AF:

0.000166

GnomAD4 exome

AF:

0.0000267

AC:

AN:

1461156

Hom.:

Cov.:

AF XY:

0.0000220

AC XY:

AN XY:

726824

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:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000342

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

Cov.:

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-C

Pathogenic:2

Mar 05, 2018

Genomic Research Center, Shahid Beheshti University of Medical Sciences

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 01, 2006

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Mucopolysaccharidosis, MPS-III-C;C4225287:Retinitis pigmentosa 73

Pathogenic:1

Jan 21, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Asp449Glyfs*21) in the HGSNAT gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in HGSNAT are known to be pathogenic (PMID: 17033958, 19479962). This variant is present in population databases (rs483352894, gnomAD 0.0009%). This premature translational stop signal has been observed in individual(s) with mucopolysaccharidosis type IIIC (PMID: 16960811, 19479962, 31228227). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 1231). For these reasons, this variant has been classified as Pathogenic. -

Retinitis pigmentosa 73

Pathogenic:1

Mar 05, 2018

Genomic Research Center, Shahid Beheshti University of Medical Sciences

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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