rs770684838

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5

The NM_000263.4(NAGLU):​c.461T>C​(p.Ile154Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,614,098 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I154V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 35)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

NAGLU
NM_000263.4 missense

Scores

11
7
1

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:1

Conservation

PhyloP100: 7.63

Publications

1 publications found
Variant links:
Genes affected
NAGLU (HGNC:7632): (N-acetyl-alpha-glucosaminidase) This gene encodes an enzyme that degrades heparan sulfate by hydrolysis of terminal N-acetyl-D-glucosamine residues in N-acetyl-alpha-D-glucosaminides. Defects in this gene are the cause of mucopolysaccharidosis type IIIB (MPS-IIIB), also known as Sanfilippo syndrome B. This disease is characterized by the lysosomal accumulation and urinary excretion of heparan sulfate. [provided by RefSeq, Jul 2008]
NAGLU Gene-Disease associations (from GenCC):
  • mucopolysaccharidosis type 3B
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Orphanet, Myriad Women’s Health
  • Charcot-Marie-Tooth disease axonal type 2V
    Inheritance: AD Classification: SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PM1
In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000263.4
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr17-42537475-T-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 558352.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.974
PP5
Variant 17-42537475-T-C is Pathogenic according to our data. Variant chr17-42537475-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2503909.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
NAGLUNM_000263.4 linkc.461T>C p.Ile154Thr missense_variant Exon 2 of 6 ENST00000225927.7 NP_000254.2 P54802A0A140VJE4
NAGLUXM_024450771.2 linkc.518T>C p.Ile173Thr missense_variant Exon 3 of 7 XP_024306539.1
NAGLUXM_047436138.1 linkc.-79+820T>C intron_variant Intron 1 of 4 XP_047292094.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
NAGLUENST00000225927.7 linkc.461T>C p.Ile154Thr missense_variant Exon 2 of 6 1 NM_000263.4 ENSP00000225927.1 P54802

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152220
Hom.:
0
Cov.:
35
show subpopulations
Gnomad AFR
AF:
0.00
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251392
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461878
Hom.:
0
Cov.:
58
AF XY:
0.00
AC XY:
0
AN XY:
727244
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53410
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
8.99e-7
AC:
1
AN:
1112008
Other (OTH)
AF:
0.00
AC:
0
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.500
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000131
AC:
2
AN:
152220
Hom.:
0
Cov.:
35
AF XY:
0.0000134
AC XY:
1
AN XY:
74362
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41454
American (AMR)
AF:
0.00
AC:
0
AN:
15294
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5190
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68034
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
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

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.0000360
Hom.:
0
Bravo
AF:
0.0000113
ExAC
AF:
0.00000824
AC:
1

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-B;C5569050:Charcot-Marie-Tooth disease axonal type 2V Pathogenic:1
Aug 11, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant disrupts the p.Ile154 amino acid residue in NAGLU. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11836372, 29979746). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. Experimental studies have shown that this missense change affects NAGLU function (PMID: 29979746). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt NAGLU protein function. ClinVar contains an entry for this variant (Variation ID: 2503909). This variant has not been reported in the literature in individuals affected with NAGLU-related conditions. This variant is present in population databases (rs770684838, gnomAD 0.006%). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 154 of the NAGLU protein (p.Ile154Thr). -

not specified Uncertain:1
Jun 26, 2025
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: NAGLU c.461T>C (p.Ile154Thr) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant allele was found at a frequency of 4e-06 in 251392 control chromosomes. To our knowledge, no occurrence of c.461T>C in individuals affected with Mucopolysaccharidosis Type IIIB (Sanfilippo Syndrome B) has been reported. At least one publication reports experimental evidence evaluating an impact on protein function in vitro. The most pronounced variant effect results in 10%-<30% of normal activity (Clark_2018). The following publications have been ascertained in the context of this evaluation (PMID: 31342580, 29979746, 28102005). ClinVar contains an entry for this variant (Variation ID: 2503909). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.35
BayesDel_addAF
Pathogenic
0.40
D
BayesDel_noAF
Pathogenic
0.51
CADD
Pathogenic
28
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.99
D;D
Eigen
Pathogenic
0.79
Eigen_PC
Pathogenic
0.68
FATHMM_MKL
Uncertain
0.92
D
LIST_S2
Uncertain
0.96
D;D
M_CAP
Pathogenic
0.65
D
MetaRNN
Pathogenic
0.97
D;D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Pathogenic
3.6
H;.
PhyloP100
7.6
PrimateAI
Uncertain
0.68
T
PROVEAN
Pathogenic
-4.6
D;.
REVEL
Pathogenic
0.96
Sift
Uncertain
0.0010
D;.
Sift4G
Uncertain
0.0020
D;D
Polyphen
0.99
D;.
Vest4
0.91
MutPred
0.85
Loss of stability (P = 0.0086);.;
MVP
1.0
MPC
1.3
ClinPred
1.0
D
GERP RS
4.3
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.1
Varity_R
0.94
gMVP
0.95

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.0
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs770684838; hg19: chr17-40689493; API