rs746006696

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1PP3_ModeratePP5

The NM_000263.4(NAGLU):​c.1991C>T​(p.Ala664Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000435 in 1,610,258 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). Synonymous variant affecting the same amino acid position (i.e. A664A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

NAGLU
NM_000263.4 missense

Scores

9
9
1

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3U:1

Conservation

PhyloP100: 4.52

Publications

3 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: Uncertain_significance. The variant received 5 ACMG points.

PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000263.4
PP3
MetaRNN computational evidence supports a deleterious effect, 0.915
PP5
Variant 17-42543997-C-T is Pathogenic according to our data. Variant chr17-42543997-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 521840.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
NAGLUNM_000263.4 linkc.1991C>T p.Ala664Val missense_variant Exon 6 of 6 ENST00000225927.7 NP_000254.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
NAGLUENST00000225927.7 linkc.1991C>T p.Ala664Val missense_variant Exon 6 of 6 1 NM_000263.4 ENSP00000225927.1
NAGLUENST00000591587.1 linkc.*960C>T 3_prime_UTR_variant Exon 4 of 4 5 ENSP00000467836.1
ENSG00000266929ENST00000585572.1 linkn.379+5242C>T intron_variant Intron 3 of 4 4

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152128
Hom.:
0
Cov.:
33
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:
0.00
Gnomad OTH
AF:
0.000479
GnomAD2 exomes
AF:
0.00000412
AC:
1
AN:
242476
AF XY:
0.00000762
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000411
AC:
6
AN:
1458130
Hom.:
0
Cov.:
32
AF XY:
0.00000414
AC XY:
3
AN XY:
725006
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33426
American (AMR)
AF:
0.00
AC:
0
AN:
44140
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25998
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39584
South Asian (SAS)
AF:
0.0000117
AC:
1
AN:
85558
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53062
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5764
European-Non Finnish (NFE)
AF:
0.00000360
AC:
4
AN:
1110370
Other (OTH)
AF:
0.00
AC:
0
AN:
60228
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.483
Heterozygous variant carriers
0
1
2
2
3
4
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:
0.00000657
AC:
1
AN:
152128
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74320
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41432
American (AMR)
AF:
0.00
AC:
0
AN:
15268
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5194
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4824
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10620
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68008
Other (OTH)
AF:
0.000479
AC:
1
AN:
2086
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:
0.00
Hom.:
0
ExAC
AF:
0.0000165
AC:
2

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:3Uncertain:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-B Pathogenic:2
Aug 05, 2024
Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 08, 2022
Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

A Homozygous missense variation in exon 6 of the NAGLU gene that results in the amino acid substitution of Valine for alanine at codon 664 was detected. The observed variant c.1991C>T (p.Ala664Val) has not been reported in the 1000 genomes and has a MAF of 0.0004% in the gnomAD databases. The in silico prediction of the variant are possibly damaging by LRT, SIFT, PROVEAN and MutationTaster2. The reference codon is conserved across species. In summary, the variant meets our criteria to be classified as likely pathogenic. -

Inborn genetic diseases Pathogenic:1
Jun 20, 2017
Ambry Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Mucopolysaccharidosis, MPS-III-B;C5569050:Charcot-Marie-Tooth disease axonal type 2V Uncertain:1
Mar 23, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 664 of the NAGLU protein (p.Ala664Val). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with Sanfilippo syndrome type B (PMID: 9443878). 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: 521840). 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. Experimental studies have shown that this missense change affects NAGLU function (PMID: 9443878, 29979746). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.49
BayesDel_addAF
Pathogenic
0.36
D
BayesDel_noAF
Pathogenic
0.28
CADD
Pathogenic
26
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.98
D
Eigen
Uncertain
0.65
Eigen_PC
Uncertain
0.56
FATHMM_MKL
Uncertain
0.83
D
LIST_S2
Uncertain
0.91
D
M_CAP
Pathogenic
0.35
D
MetaRNN
Pathogenic
0.92
D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Pathogenic
3.2
M
PhyloP100
4.5
PrimateAI
Uncertain
0.50
T
PROVEAN
Uncertain
-3.1
D
REVEL
Pathogenic
0.86
Sift
Uncertain
0.015
D
Sift4G
Uncertain
0.041
D
Polyphen
1.0
D
Vest4
0.38
MutPred
0.90
Loss of helix (P = 0.0558);
MVP
0.97
MPC
1.1
ClinPred
0.97
D
GERP RS
4.5
Varity_R
0.92
gMVP
0.67
Mutation Taster
=19/81
disease causing (ClinVar)

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: rs746006696; hg19: chr17-40696015; API