17-80217084-G-C
Variant summary
Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2PP3_ModeratePP5_Very_Strong
The NM_000199.5(SGSH):c.197C>G(p.Ser66Trp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000156 in 1,600,772 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
Consequence
NM_000199.5 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 12 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000105 AC: 16AN: 152244Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.0000928 AC: 21AN: 226198Hom.: 0 AF XY: 0.0000896 AC XY: 11AN XY: 122814
GnomAD4 exome AF: 0.000161 AC: 233AN: 1448528Hom.: 0 Cov.: 31 AF XY: 0.000150 AC XY: 108AN XY: 719644
GnomAD4 genome AF: 0.000105 AC: 16AN: 152244Hom.: 0 Cov.: 33 AF XY: 0.0000807 AC XY: 6AN XY: 74376
ClinVar
Submissions by phenotype
Mucopolysaccharidosis, MPS-III-A Pathogenic:17
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NM_000199.3(SGSH):c.197C>G(S66W) is classified as pathogenic in the context of mucopolysaccharidosis type IIIA. Sources cited for classification include the following: PMID 10601282, 15542396, 9158154, 11182930 and 9554748. Classification of NM_000199.3(SGSH):c.197C>G(S66W) is based on the following criteria: This is a well-established pathogenic variant in the literature that has been observed more frequently in patients with clinical diagnoses than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -
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This sequence change replaces serine, which is neutral and polar, with tryptophan, which is neutral and slightly polar, at codon 66 of the SGSH protein (p.Ser66Trp). This variant is present in population databases (rs104894637, gnomAD 0.02%). This missense change has been observed in individual(s) with mucopolysaccharidosis type IIIA (PMID: 9158154, 9285796, 9554748, 15542396, 21061399, 22976768). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 5111). 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) indicates that this missense variant is expected to disrupt SGSH protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects SGSH function (PMID: 10601282, 15542396). For these reasons, this variant has been classified as Pathogenic. -
PS3, PS4, PP3 -
This sequence variant is a single nucleotide substitution (C>G) at position 197 of the coding sequence of the SGSH gene that results in a serine to tryptophan amino acid change at residue 66 of the N-sulfoglucosamine sulfohydrolase protein. This is a previously reported variant (ClinVar 5111) that has been commonly observed in homozygous or compound heterozygous state in individuals affected by Sanfilippo syndrome type A (PMID: 9158154, 9285796, 9554748). This variant is present in 249 of 1600772 alleles (0.01555%) in the gnomAD v4.0.0 population dataset. Multiple bioinformatic tools predict that this amino acid change would be damaging, and the Ser66 residue at this position is highly conserved across the vertebrate species examined. Functional studies indicate that the variant protein has 15% or less activity (PMID: 10601282, 15542396). Based upon the evidence, we consider this variant to be pathogenic. ACMG Criteria: PM3, PP3, PS3, PS4 -
PS3: Low in vitro enzymatic activity. PP1: Cosegregation with disease in multiple affected family members (strong evidence). PM2: Very low frequency in GnomAD. PP5: reputable source report variant as pathogenic. -
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This variant has been previously reported as disease-causing PMIDs 10601282, 9554748, 29023963, 21228398, 9158154, 24816101, 15542396, 10521831, 25807448. -
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not provided Pathogenic:3
SGSH: PM3:Very Strong, PM2, PP3, PS3:Supporting -
Published functional studies demonstrate a damaging effect with reduced protein quantity and activity (Perkins et al., 1999; Montfort et al., 2004); 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: 10521831, 25807448, 24816101, 15542396, 31980526, 9554748, 10601282, 9158154, 21228398, 29023963, 30809705, 34440436, 34349725, 31589614) -
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Inborn genetic diseases Pathogenic:1
The c.197C>G (p.S66W) alteration is located in exon 2 (coding exon 2) of the SGSH gene. This alteration results from a C to G substitution at nucleotide position 197, causing the serine (S) at amino acid position 66 to be replaced by a tryptophan (W). Based on data from the Genome Aggregation Database (gnomAD) database, the SGSH c.197C>G alteration was observed in 0.01% (23/257594) of total alleles studied, with a frequency of 0.02% (23/117902) in the European (non-Finnish) subpopulation. This mutation has been detected as heterozygous, compound heterozygous, and homozygous, in individuals with typical severe presentations of Mucopolysaccaridosis type IIIA (Sanfilippo syndrome type A) (Blanch, 1997; Di Natale, 1998; Valstar, 2010; Ouesleti, 2011; Delgadillo, 2013; Shapiro, 2016; Knottnerus, 2017; Zanetti, 2019). In addition, one functional study showed that this mutation results in a drastically reduced level of functional protein as well as lowered specific activity (Perkins, 1999). This amino acid position is highly conserved in available vertebrate species. The in silico prediction for the p.S66W alteration is inconclusive. Based on the available evidence, this alteration is classified as pathogenic. -
SGSH-related disorder Pathogenic:1
The SGSH c.197C>G variant is predicted to result in the amino acid substitution p.Ser66Trp. This variant was reported in multiple individuals mucopolysaccharidosis type IIIA (Sanfilippo A) (Blanch. 1997. PubMed ID: 9158154; Knottnerus. 2017. PubMed ID: 29023963; Barone. 2021. PubMed ID: 34349725; Table S4, Barbosa-Gouveia. 2021. PubMed ID: 34440436). Functional in vitro studies found this variant has reduced expression and residual activity (Perkins. 1999. PubMed ID: 10601282). This variant is reported in 0.020% of alleles in individuals of European (Non-Finnish) descent in gnomAD. This variant is interpreted as pathogenic. -
Sanfilippo syndrome Pathogenic:1
Variant summary: The SGSH c.197C>G (p.Ser66Trp) variant involves the alteration of a conserved nucleotide located in the Alkaline-phosphatase-like domain of the protein (InterPro). 4/4 in silico tools predict a damaging outcome for this variant (SNPsandGO not captured due to low reliability index). This variant was found in 23/251298 control chromosomes at a frequency of 0.0000915, which does not exceed the estimated maximal expected allele frequency of a pathogenic SGSH variant (0.0032275). This variant has been reported in numerous patients both homozygously and compound heterozygously. Functional study showed variant with 10% of WT enzyme activity (Montfort_MGM_2004) In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as pathogenic. Taken together, this variant is classified as pathogenic. -
Mucopolysaccharidosis Other:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at