17-42543921-G-T

Variant names:

• chr17-42543921-G-T
• rs555145190
• NM_000263.4:c.1915G>T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000263.4(NAGLU):​c.1915G>T​(p.Glu639*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000275 in 1,454,666 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: NAGLU NM_000263.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 6.60

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]

ENSG00000266929 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 8 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-42543921-G-T is Pathogenic according to our data. Variant chr17-42543921-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 522822.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NAGLU	NM_000263.4	c.1915G>T	p.Glu639*	stop_gained	Exon 6 of 6	ENST00000225927.7	NP_000254.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NAGLU	ENST00000225927.7	c.1915G>T	p.Glu639*	stop_gained	Exon 6 of 6	1	NM_000263.4	ENSP00000225927.1
NAGLU	ENST00000591587.1	c.*884G>T		3_prime_UTR_variant	Exon 4 of 4	5		ENSP00000467836.1
ENSG00000266929	ENST00000585572.1	n.379+5166G>T		intron_variant	Intron 3 of 4	4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000275 AC: 4 AN: 1454666 Hom.: 0 Cov.: 32 AF XY: 0.00000277 AC XY: 2 AN XY: 723142

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: 0.00000361

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Mucopolysaccharidosis, MPS-III-B Pathogenic:2

Feb 09, 2017

Undiagnosed Diseases Network, NIH

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 23, 2017

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

May 14, 2019

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Feb 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Glu639*) in the NAGLU gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 105 amino acid(s) of the NAGLU protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with mucopolysaccharidosis type III (PMID: 16151907, 35848209). ClinVar contains an entry for this variant (Variation ID: 522822). This variant disrupts a region of the NAGLU protein in which other variant(s) (p.Gln706*) have been determined to be pathogenic (PMID: 9443875, 29661560; Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.66	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	39
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Uncertain	0.97	D
Vest4		0.70
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs555145190; hg19: chr17-40695939; COSMIC: COSV56795748; COSMIC: COSV56795748;