Genetic Variant NMNAT2:p.Gln135SerfsTer42 (chr1-183286706-TG-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_015039.4(NMNAT2):c.403delC(p.Gln135SerfsTer42) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000685 in 1,460,300 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

NMNAT2
NM_015039.4 frameshift

Scores

Not classified

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 6.65

Publications

0 publications found

Variant links:

Genes affected

NMNAT2 (HGNC:16789): (nicotinamide nucleotide adenylyltransferase 2) This gene product belongs to the nicotinamide mononucleotide adenylyltransferase (NMNAT) enzyme family, members of which catalyze an essential step in NAD (NADP) biosynthetic pathway. Unlike the other human family member, which is localized to the nucleus, and is ubiquitously expressed; this enzyme is cytoplasmic, and is predominantly expressed in the brain. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

NMNAT2 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NMNAT2	NM_015039.4 link	c.403delC	p.Gln135SerfsTer42	frameshift_variant	Exon 5 of 11	ENST00000287713.7	NP_055854.1	Q9BZQ4-1
NMNAT2	NM_170706.4 link	c.388delC	p.Gln130SerfsTer42	frameshift_variant	Exon 5 of 11		NP_733820.1	Q9BZQ4-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
NMNAT2	ENST00000287713.7 link	c.403delC	p.Gln135SerfsTer42	frameshift_variant	Exon 5 of 11	1	NM_015039.4	ENSP00000287713.6	Q9BZQ4-1
NMNAT2	ENST00000294868.8 link	c.388delC	p.Gln130SerfsTer42	frameshift_variant	Exon 5 of 11	1		ENSP00000294868.4	Q9BZQ4-2
NMNAT2	ENST00000473046.1 link	n.273delC		non_coding_transcript_exon_variant	Exon 3 of 5	1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00

AC:

AN:

249410

AF XY:

0.00

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460300

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726382

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33474

American (AMR)

AF:

0.00

AC:

AN:

44400

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39664

South Asian (SAS)

AF:

0.0000117

AC:

AN:

85724

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111386

Other (OTH)

AF:

0.00

AC:

AN:

60346

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.225

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

6.6

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over