rs762402992

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_152419.3(HGSNAT):​c.744-2A>C variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,607,888 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 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

HGSNAT
NM_152419.3 splice_acceptor, intron

Scores

3
1
3
Splicing: ADA: 1.000
2

Clinical Significance

Likely pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 7.48

Publications

1 publications found
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 Gene-Disease associations (from GenCC):
  • mucopolysaccharidosis type 3
    Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
  • mucopolysaccharidosis type 3C
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, Genomics England PanelApp, Ambry Genetics, G2P
  • retinitis pigmentosa 73
    Inheritance: AR Classification: STRONG, MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
  • retinitis pigmentosa
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 5.8, offset of -38, new splice context is: agcccttccttttcacatAGcaa. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 8-43172308-A-C is Pathogenic according to our data. Variant chr8-43172308-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1948100.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HGSNATNM_152419.3 linkc.744-2A>C splice_acceptor_variant, intron_variant Intron 7 of 17 ENST00000379644.9 NP_689632.2 Q68CP4-2Q8IVU6

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HGSNATENST00000379644.9 linkc.744-2A>C splice_acceptor_variant, intron_variant Intron 7 of 17 2 NM_152419.3 ENSP00000368965.4 Q68CP4-2
HGSNATENST00000520704.1 linkn.*193-2A>C splice_acceptor_variant, intron_variant Intron 8 of 9 1 ENSP00000429109.1 E5RJC4
HGSNATENST00000522082.5 linkc.-18A>C upstream_gene_variant 4 ENSP00000430151.1 E5RGH7

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152208
Hom.:
0
Cov.:
32
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:
0.00
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
6.87e-7
AC:
1
AN:
1455680
Hom.:
0
Cov.:
28
AF XY:
0.00000138
AC XY:
1
AN XY:
724608
show subpopulations
African (AFR)
AF:
0.0000300
AC:
1
AN:
33362
American (AMR)
AF:
0.00
AC:
0
AN:
44714
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26102
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39666
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86162
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53390
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5756
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1106380
Other (OTH)
AF:
0.00
AC:
0
AN:
60148
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152208
Hom.:
0
Cov.:
32
AF XY:
0.0000134
AC XY:
1
AN XY:
74358
show subpopulations
African (AFR)
AF:
0.0000241
AC:
1
AN:
41456
American (AMR)
AF:
0.00
AC:
0
AN:
15284
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5196
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10614
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68032
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.675
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000756

ClinVar

Significance: Likely pathogenic
Submissions summary: Pathogenic:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-C;C4225287:Retinitis pigmentosa 73 Pathogenic:1
Mar 04, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change affects an acceptor splice site in intron 7 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 not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with mucopolysaccharidosis type III (PMID: 19479962, 33879512). ClinVar contains an entry for this variant (Variation ID: 1948100). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.63
D
BayesDel_noAF
Benign
-0.21
CADD
Pathogenic
33
DANN
Benign
0.96
Eigen
Pathogenic
0.90
Eigen_PC
Pathogenic
0.68
FATHMM_MKL
Uncertain
0.96
D
PhyloP100
7.5
GERP RS
5.4
PromoterAI
0.053
Neutral
Mutation Taster
=0/100
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.94
SpliceAI score (max)
0.98
Details are displayed if max score is > 0.2
DS_AG_spliceai
0.75
Position offset: -36
DS_AL_spliceai
0.98
Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs762402992; hg19: chr8-43027451; API