NM_152419.3:c.1250+1G>A

Variant names:

Variant summary

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

The NM_152419.3(HGSNAT):c.1250+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000242 in 1,613,654 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: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

HGSNAT
NM_152419.3 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11

Conservation

PhyloP100: 8.78

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

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 8-43191596-G-A is Pathogenic according to our data. Variant chr8-43191596-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 96500.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr8-43191596-G-A is described in Lovd as [Pathogenic]. Variant chr8-43191596-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HGSNAT	NM_152419.3 link	c.1250+1G>A		splice_donor_variant, intron_variant	Intron 12 of 17	ENST00000379644.9	NP_689632.2	Q68CP4-2Q8IVU6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HGSNAT	ENST00000379644.9 link	c.1250+1G>A		splice_donor_variant, intron_variant	Intron 12 of 17	2	NM_152419.3	ENSP00000368965.4		Q68CP4-2

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152188

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000401

AC:

AN:

249078

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135144

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:

0.00000886

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000253

AC:

AN:

1461466

Hom.:

Cov.:

AF XY:

0.0000234

AC XY:

AN XY:

727002

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:

0.0000315

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152188

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74354

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000688

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.00000827

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:11

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-C

Pathogenic:3

Apr 28, 2017

Illumina Laboratory Services, Illumina

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The HGSNAT c.1250+1G>A variant occurs in a canonical splice site (donor) and is therefore predicted to disrupt or distort the normal gene product. The c.1250+1G>A variant has been reported in two studies and is found in a compound heterozygous state in two patients with mucopolysaccharidosis, type III, one of whom had another known pathogenic variant in trans (HrebÃcek et al. 2006; FernÃ¡ndez-Marmiesse et al. 2014). The c.1250+1G>A variant was absent from 200 control alleles and is reported at a frequency of 0.00001 in the European (non-Finnish) population from the Exome Aggregation Consortium but this is based on one allele in a region of good sequencing coverage so the variant is presumed to be rare. Based on the evidence and the potential impact of splice donor variants, the c.1250+1G>A variant is classified as likely pathogenic for mucopolysaccharidosis, type III. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

Nov 01, 2021

Myriad Genetics, Inc.

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

NM_152419.2(HGSNAT):c.1250+1G>A is a canonical splice variant classified as pathogenic in the context of mucopolysaccharidosis type IIIC. c.1250+1G>A has been observed in cases with relevant disease (PMID: 31228227, 24767253). Functional assessments of this variant are not available in the literature. c.1250+1G>A has been observed in population frequency databases (gnomAD: OTH 0.01%). In summary, NM_152419.2(HGSNAT):c.1250+1G>A is a canonical splice variant in a gene where loss of function is a known mechanism of disease, is predicted to disrupt protein function, and has been observed more frequently in cases with the relevant disease than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -

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

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 12 of the HGSNAT 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 HGSNAT are known to be pathogenic (PMID: 17033958, 19479962). This variant is present in population databases (rs398124544, gnomAD 0.002%). Disruption of this splice site has been observed in individuals with autosomal recessive mucopolysaccharidosis type III (PMID: 17033958, 24767253). This variant is also known as c.1334+1G>A. ClinVar contains an entry for this variant (Variation ID: 96500). 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. -

Apr 22, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Pathogenic:2

Dec 21, 2021

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Observed in a patient with features consistent with mucopolysaccharidosis 3C (MPS 3C) who harbored a second variant in published literature (Fernandez-Marmiesse et al., 2014); Reported with a benign variant, phase unknown, by whole exome sequencing in a patient with late onset retinitis pigmentosa in published literature (Schiff et al., 2020); Canonical splice site variant predicted to result in a null allele in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 25525159, 16199547, 33578874, 19479962, 32770643, 31228227, 17033958, 24767253) -

Jun 18, 2013

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Retinal dystrophy

Pathogenic:2

Apr 18, 2019

Blueprint Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 01, 2020

Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Retinitis pigmentosa 73

Pathogenic:1

Jan 31, 2022

MGZ Medical Genetics Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sanfilippo syndrome

Pathogenic:1

Oct 14, 2019

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HGSNAT c.1250+1G>A is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Five predict the variant abolishes a 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4e-06 in 249078 control chromosomes (gnomAD). c.1250+1G>A has been reported in the literature in individuals affected with Mucopolysaccharidosis Type IIIC (Sanfilippo Syndrome C)(Feldhammer_2009, Fernandez-Marmiesse_2014, Hrebicek_2006, Martins_2019). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three ClinVar submissions (evaluation after 2014) cite the variant twice as pathogenic and once as likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.28

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.96

FATHMM_MKL

Uncertain

0.95

GERP RS

5.2

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

0.95

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.95

Position offset: -1

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