17-42536416-C-G

Position:

• chr17-42536416-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PM5 PP3_Strong PP5

The NM_000263.4(NAGLU):​c.144C>G​(p.Phe48Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. F48C) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: NAGLU NM_000263.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 0.253

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.977
• PP5: Variant 17-42536416-C-G is Pathogenic according to our data. Variant chr17-42536416-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 555776.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NAGLU	NM_000263.4	c.144C>G	p.Phe48Leu	missense_variant	1/6	ENST00000225927.7	NP_000254.2
NAGLU	XM_047436138.1	c.-318C>G		5_prime_UTR_premature_start_codon_gain_variant	1/5		XP_047292094.1
NAGLU	XM_024450771.2	c.144C>G	p.Phe48Leu	missense_variant	1/7		XP_024306539.1
NAGLU	XM_047436138.1	c.-318C>G		5_prime_UTR_variant	1/5		XP_047292094.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NAGLU	ENST00000225927.7	c.144C>G	p.Phe48Leu	missense_variant	1/6	1	NM_000263.4	ENSP00000225927.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1098134 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 531702

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Nov 29, 2023

Not observed in large population cohorts (gnomAD); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge -

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

Dec 01, 2023

This sequence change replaces phenylalanine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 48 of the NAGLU protein (p.Phe48Leu). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with mucopolysaccharidosis type IIIB (PMID: 10094189). ClinVar contains an entry for this variant (Variation ID: 555776). 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 80%. Experimental studies have shown that this missense change affects NAGLU function (PMID: 11068184). This variant disrupts the p.Phe48 amino acid residue in NAGLU. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9832037, 29979746). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Mucopolysaccharidosis, MPS-III-B Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

Dec 21, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.30
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D
Eigen	Benign	0.042
Eigen_PC	Benign	-0.13
FATHMM_MKL	Benign	0.41	N
LIST_S2	Benign	0.53	T
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.93	D
MutationAssessor	Uncertain	2.8	M
PrimateAI	Pathogenic	0.95	D
PROVEAN	Uncertain	-4.2	D
REVEL	Pathogenic	0.73
Sift	Benign	0.034	D
Sift4G	Benign	0.10	T
Polyphen		0.98	D
Vest4		0.74
MutPred		0.86		Gain of disorder (P = 0.0662);
MVP		0.98
MPC		1.2
ClinPred		1.0	D
GERP RS		3.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.82
gMVP		0.76

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: rs104894599; hg19: chr17-40688434;