rs749140168
Variant summary
Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1PM5PP5BP4
The NM_000263.4(NAGLU):c.1000G>A(p.Val334Ile) variant causes a missense change. The variant allele was found at a frequency of 0.000018 in 1,613,216 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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. V334F) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000263.4 missense
Scores
Clinical Significance
Conservation
Publications
- mucopolysaccharidosis type 3BInheritance: 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 2VInheritance: AD Classification: SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
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ACMG classification
Our verdict: Uncertain_significance. The variant received 4 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt | 
|---|---|---|---|---|---|---|---|---|
| NAGLU | NM_000263.4 | c.1000G>A | p.Val334Ile | missense_variant | Exon 5 of 6 | ENST00000225927.7 | NP_000254.2 | 
Ensembl
Frequencies
GnomAD3 genomes  0.0000263  AC: 4AN: 152162Hom.:  0  Cov.: 31 show subpopulations 
GnomAD2 exomes  AF:  0.0000240  AC: 6AN: 250414 AF XY:  0.0000369   show subpopulations 
GnomAD4 exome  AF:  0.0000171  AC: 25AN: 1460936Hom.:  0  Cov.: 32 AF XY:  0.0000206  AC XY: 15AN XY: 726810 show subpopulations 
Age Distribution
GnomAD4 genome  0.0000263  AC: 4AN: 152280Hom.:  0  Cov.: 31 AF XY:  0.0000269  AC XY: 2AN XY: 74462 show subpopulations 
Age Distribution
ClinVar
Submissions by phenotype
Tip-toe gait    Pathogenic:1 
Hereditary motor sensory neuropathy (HMSN), also known as Charcot-Marie-Tooth Disease (CMT), is the most commonly inherited peripheral polyneuropathy. It constitutes a group of inherited, progressive, motor and sensory peripheral nerve disorders with properties of demyelination, axonal degeneration, or both. It is classified by clinical characteristics, modes of inheritance, electrophysiologic features, metabolic defects, and specific gene markers. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. -
not provided    Uncertain:1 
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Mucopolysaccharidosis, MPS-III-B;C5569050:Charcot-Marie-Tooth disease axonal type 2V    Uncertain:1 
This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 334 of the NAGLU protein (p.Val334Ile). This variant is present in population databases (rs749140168, gnomAD 0.01%). This missense change has been observed in individual(s) with mucopolysaccarhidosis type IIIB (PMID: 33747789). ClinVar contains an entry for this variant (Variation ID: 623899). 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 not expected to disrupt NAGLU protein function. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on NAGLU function (PMID: 29979746). This variant disrupts the p.Val334 amino acid residue in NAGLU. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10094189; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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: 
Splicing
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at