NM_018946.4:c.398G>A

Variant names:

• chr9-98076967-G-A
• rs878852980
• NM_018946.4:c.398G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2 PM5 PP3_Strong

The NM_018946.4(NANS):​c.398G>A​(p.Gly133Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,458,960 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G133V) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: NANS NM_018946.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.58
• Publications: 0 publications found

Genes affected

NANS (HGNC:19237): (N-acetylneuraminate synthase) This gene encodes an enzyme that functions in the biosynthetic pathways of sialic acids. In vitro, the encoded protein uses N-acetylmannosamine 6-phosphate and mannose 6-phosphate as substrates to generate phosphorylated forms of N-acetylneuraminic acid (Neu5Ac) and 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN), respectively; however, it exhibits much higher activity toward the Neu5Ac phosphate product. In insect cells, expression of this gene results in Neu5Ac and KDN production. This gene is related to the E. coli sialic acid synthase gene neuB, and it can partially restore sialic acid synthase activity in an E. coli neuB-negative mutant. [provided by RefSeq, Jul 2008]

TRIM14 (HGNC:16283): (tripartite motif containing 14) The protein encoded by this gene is a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. The protein localizes to cytoplasmic bodies and its function has not been determined. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2010]

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-98076967-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 235188.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_018946.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NANS	NM_018946.4	MANE Select	c.398G>A	p.Gly133Glu	missense	Exon 3 of 6	NP_061819.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NANS	ENST00000210444.6	TSL:1 MANE Select	c.398G>A	p.Gly133Glu	missense	Exon 3 of 6	ENSP00000210444.5	Q9NR45
	NANS	ENST00000924305.1		c.452G>A	p.Gly151Glu	missense	Exon 4 of 7	ENSP00000594364.1
	NANS	ENST00000924304.1		c.395G>A	p.Gly132Glu	missense	Exon 3 of 6	ENSP00000594363.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1458960 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 725568

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33334

American (AMR) AF: 0.00 AC: 0 AN: 44176

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26090

East Asian (EAS) AF: 0.00 AC: 0 AN: 39640

South Asian (SAS) AF: 0.00 AC: 0 AN: 85172

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53302

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111164

Other (OTH) AF: 0.00 AC: 0 AN: 60322

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.20
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Benign	0.16	T
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.87	D
M_CAP	Benign	0.054	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Benign	-0.34	T
MutationAssessor	Pathogenic	3.1	M
PhyloP100		7.6
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-5.7	D
REVEL	Uncertain	0.61
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.014	D
Polyphen		0.94	P
Vest4		0.98
MutPred		0.89		Loss of catalytic residue at S134 (P = 0.073)
MVP		0.86
MPC		0.90
ClinPred		0.99	D
GERP RS		5.7
PromoterAI		-0.0016	Neutral
Varity_R		0.98
gMVP		0.95
Mutation Taster		=2/98	disease causing

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

Other links and lift over

dbSNP: rs878852980; hg19: chr9-100839249;