chr17-42543921-G-A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate

The NM_000263.4(NAGLU):​c.1915G>A​(p.Glu639Lys) variant causes a missense change. The variant allele was found at a frequency of 0.00000311 in 1,606,840 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E639Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

NAGLU
NM_000263.4 missense

Scores

6
10
3

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 6.60

Publications

2 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: Likely_pathogenic. The variant received 6 ACMG points.

PM1
In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 12 uncertain in NM_000263.4
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.896

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
NAGLUNM_000263.4 linkc.1915G>A p.Glu639Lys missense_variant Exon 6 of 6 ENST00000225927.7 NP_000254.2 P54802A0A140VJE4

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
NAGLUENST00000225927.7 linkc.1915G>A p.Glu639Lys missense_variant Exon 6 of 6 1 NM_000263.4 ENSP00000225927.1 P54802
NAGLUENST00000591587.1 linkc.*884G>A 3_prime_UTR_variant Exon 4 of 4 5 ENSP00000467836.1 K7EQH9
ENSG00000266929ENST00000585572.1 linkn.379+5166G>A intron_variant Intron 3 of 4 4

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152174
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
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
GnomAD2 exomes
AF:
0.00
AC:
0
AN:
235488
AF XY:
0.00
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:
0.00000275
AC:
4
AN:
1454666
Hom.:
0
Cov.:
32
AF XY:
0.00000277
AC XY:
2
AN XY:
723142
show subpopulations
African (AFR)
AF:
0.0000300
AC:
1
AN:
33360
American (AMR)
AF:
0.00
AC:
0
AN:
43716
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25922
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39442
South Asian (SAS)
AF:
0.00
AC:
0
AN:
85174
European-Finnish (FIN)
AF:
0.0000191
AC:
1
AN:
52240
Middle Eastern (MID)
AF:
0.000174
AC:
1
AN:
5758
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1109028
Other (OTH)
AF:
0.0000167
AC:
1
AN:
60026
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.438
Heterozygous variant carriers
0
1
1
2
2
3
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:
152174
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74350
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41452
American (AMR)
AF:
0.0000655
AC:
1
AN:
15272
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3466
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5194
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10612
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68028
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.325
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: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-B;C5569050:Charcot-Marie-Tooth disease axonal type 2V Uncertain:1
Mar 18, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 639 of the NAGLU protein (p.Glu639Lys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with NAGLU-related conditions. 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. 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
Benign
0.32
BayesDel_addAF
Pathogenic
0.23
D
BayesDel_noAF
Uncertain
0.10
CADD
Uncertain
25
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.99
D
Eigen
Uncertain
0.61
Eigen_PC
Uncertain
0.60
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Benign
0.79
T
M_CAP
Pathogenic
0.66
D
MetaRNN
Pathogenic
0.90
D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Uncertain
2.9
M
PhyloP100
6.6
PrimateAI
Uncertain
0.51
T
PROVEAN
Uncertain
-3.2
D
REVEL
Pathogenic
0.86
Sift
Uncertain
0.0030
D
Sift4G
Uncertain
0.0060
D
Polyphen
0.88
P
Vest4
0.29
MutPred
0.87
Gain of methylation at E639 (P = 0.0134);
MVP
0.97
MPC
0.78
ClinPred
0.97
D
GERP RS
4.7
Varity_R
0.93
gMVP
0.56

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: rs555145190; hg19: chr17-40695939; API