rs118204025

Positions:

• chr17-42541127-C-G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The ENST00000225927.7(NAGLU):​c.942C>G​(p.Phe314Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,792 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. F314S) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: NAGLU ENST00000225927.7 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2 U:1
• Conservation: PhyloP100: 3.25

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]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in ENST00000225927.7
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-42541125-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1495526.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 17-42541127-C-G is Pathogenic according to our data. Variant chr17-42541127-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 1570.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NAGLU	NM_000263.4	c.942C>G	p.Phe314Leu	missense_variant	5/6	ENST00000225927.7	NP_000254.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NAGLU	ENST00000225927.7	c.942C>G	p.Phe314Leu	missense_variant	5/6	1	NM_000263.4	ENSP00000225927	P1
NAGLU	ENST00000592454.1	c.39C>G	p.Phe13Leu	missense_variant	1/2	2		ENSP00000468665
NAGLU	ENST00000591587.1	c.360-1901C>G		intron_variant		5		ENSP00000467836
NAGLU	ENST00000586516.5			downstream_gene_variant		2		ENSP00000467135

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251356 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135856

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461792 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727206

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000671

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-B Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jan 01, 2002

- -

Mucopolysaccharidosis, MPS-III-B;C5569050:Charcot-Marie-Tooth disease axonal type 2V Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 12, 2024

This sequence change replaces phenylalanine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 314 of the NAGLU protein (p.Phe314Leu). This variant is present in population databases (rs118204025, gnomAD 0.003%). This missense change has been observed in individual(s) with mucopolysaccharidosis IIIB (PMID: 12202988, 27243974). 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: 1570). 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 with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

NAGLU-related disorder Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Nov 14, 2023

The NAGLU c.942C>G variant is predicted to result in the amino acid substitution p.Phe314Leu. This variant has been reported in the homozygous state or with a second NAGLU variant in individuals with mucopolysaccharidosis type IIIB (Supplementary Table S2, Yubero et al. 2016. PubMed ID: 27243974; Tanaka et al. 2002. PubMed ID: 12202988). This variant is reported in 0.0029% of alleles in individuals of Latino descent in gnomAD (http://gnomad.broadinstitute.org/variant/17-40693145-C-G). Although we suspect that this variant may be pathogenic, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.47
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.97	D
Eigen	Benign	-0.29
Eigen_PC	Benign	-0.24
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	2.9	M
MutationTaster	Benign	1.0	A
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-5.6	D
REVEL	Pathogenic	0.72
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.037	D
Polyphen		0.15	B
Vest4		1.0
MutPred		0.97		Loss of sheet (P = 0.1158);
MVP		0.90
MPC		0.97
ClinPred		0.96	D
GERP RS		1.8
Varity_R		0.78
gMVP		0.90

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

LitVar

Other links and lift over

dbSNP: rs118204025; hg19: chr17-40693145;