rs387906347

chr9-36219856-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5

The NM_001128227.3(GNE):c.1891G>A(p.Ala631Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,780 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A631V) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GNE NM_001128227.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6 U:1
• Conservation: PhyloP100: 7.33

Genes affected

GNE (HGNC:23657): (glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase) The protein encoded by this gene is a bifunctional enzyme that initiates and regulates the biosynthesis of N-acetylneuraminic acid (NeuAc), a precursor of sialic acids. It is a rate-limiting enzyme in the sialic acid biosynthetic pathway. Sialic acid modification of cell surface molecules is crucial for their function in many biologic processes, including cell adhesion and signal transduction. Differential sialylation of cell surface molecules is also implicated in the tumorigenicity and metastatic behavior of malignant cells. Mutations in this gene are associated with sialuria, autosomal recessive inclusion body myopathy, and Nonaka myopathy. Alternative splicing of this gene results in transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

CLTA (HGNC:2090): (clathrin light chain A) Clathrin is a large, soluble protein composed of heavy and light chains. It functions as the main structural component of the lattice-type cytoplasmic face of coated pits and vesicles which entrap specific macromolecules during receptor-mediated endocytosis. This gene encodes one of two clathrin light chain proteins which are believed to function as regulatory elements. Alternative splicing results in multiple transcript variants. Related pseudogenes have been identified on chromosomes 8 and 12. [provided by RefSeq, May 2010]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a helix (size 8) in uniprot entity GLCNE_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_001128227.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-36219855-G-A is described in Lovd as [Pathogenic].
• PP2: Missense variant where missense usually causes diseases, GNE
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.926
• PP5: Variant 9-36219856-C-T is Pathogenic according to our data. Variant chr9-36219856-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 286014.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=3, Pathogenic=2, Uncertain_significance=1}. Variant chr9-36219856-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GNE	NM_001128227.3	c.1891G>A	p.Ala631Thr	missense_variant	10/12	ENST00000396594.8
GNE	NM_005476.7	c.1798G>A	p.Ala600Thr	missense_variant	10/12	ENST00000642385.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GNE	ENST00000396594.8	c.1891G>A	p.Ala631Thr	missense_variant	10/12	1	NM_001128227.3
GNE	ENST00000642385.2	c.1798G>A	p.Ala600Thr	missense_variant	10/12		NM_005476.7	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461780 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727206

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:6 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

GNE myopathy Pathogenic:4

Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Feb 23, 2018	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 22, 2024	Variant summary: GNE c.1891G>A (p.Ala631Thr) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251472 control chromosomes (gnomAD). c.1891G>A has been reported in the literature in individuals affected with hereditary inclusion-body myopathy (examples: Broccolini_2004, Huizing_2003, and Eisenberg_2001). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in >50%-90% of normal activity (Penner_2006). A different variant (c.1892C>T/p.Ala631Val) affecting this residue has been classified pathogenic in ClinVar (CV ID 6035). The following publications have been ascertained in the context of this evaluation (PMID: 15146476, 11528398, 19596068, 16503651). ClinVar contains an entry for this variant (Variation ID: 286014). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	May 16, 2023	- -

not provided Pathogenic:1 Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Mar 16, 2016	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Feb 03, 2023	Not observed at significant frequency in large population cohorts (gnomAD); Missense variants in this gene are often considered pathogenic (HGMD); In silico analysis supports that this missense variant does not alter protein structure/function; Also known as A600T using alternate nomenclature; This variant is associated with the following publications: (PMID: 19917666, 24796702, 19596068, 15146476) -

Sialuria;C1853926:GNE myopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Apr 26, 2023

ClinVar contains an entry for this variant (Variation ID: 286014). This variant is also known as p.A600T. This missense change has been observed in individuals with hereditary inclusion body myopathy and distal myopathy (PMID: 11528398, 15146476, 18555875). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 631 of the GNE protein (p.Ala631Thr). For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Ala631 amino acid residue in GNE. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 12497639, 22507750, 24027297). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects GNE function (PMID: 16503651). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on GNE protein function. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.47
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
Cadd	Pathogenic	29
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D;.;D;.;.;.;D
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Uncertain	0.95	D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M;.;M;.;.;.;M
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.74	T
Polyphen		0.99	D;D;D;.;.;.;D
Vest4		0.95, 0.95, 0.93, 0.91, 0.92
MutPred		0.79		Gain of phosphorylation at A600 (P = 0.022);.;Gain of phosphorylation at A600 (P = 0.022);.;.;.;Gain of phosphorylation at A600 (P = 0.022);
MVP		0.99
MPC		1.4
ClinPred		0.98	D
GERP RS		5.8
Varity_R		0.81
gMVP		0.91

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: rs387906347; hg19: chr9-36219853;