1-9972111-C-A

Position:

• chr1-9972111-C-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_022787.4(NMNAT1):​c.38C>A​(p.Ala13Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A13T) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: NMNAT1 NM_022787.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.54

Genes affected

NMNAT1 (HGNC:17877): (nicotinamide nucleotide adenylyltransferase 1) This gene encodes an enzyme which catalyzes a key step in the biosynthesis of nicotinamide adenine dinucleotide (NAD). The encoded enzyme is one of several nicotinamide nucleotide adenylyltransferases, and is specifically localized to the cell nucleus. Activity of this protein leads to the activation of a nuclear deacetylase that functions in the protection of damaged neurons. Mutations in this gene have been associated with Leber congenital amaurosis 9. Alternative splicing results in multiple transcript variants. Pseudogenes of this gene are located on chromosomes 1, 3, 4, 14, and 15. [provided by RefSeq, Jul 2014]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_022787.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-9972110-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 195375.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Likely_pathogenic=4, Uncertain_significance=2}.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963
• PP5: Variant 1-9972111-C-A is Pathogenic according to our data. Variant chr1-9972111-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1376825.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NMNAT1	NM_022787.4	c.38C>A	p.Ala13Asp	missense_variant	2/5	ENST00000377205.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NMNAT1	ENST00000377205.6	c.38C>A	p.Ala13Asp	missense_variant	2/5	1	NM_022787.4	P1
NMNAT1	ENST00000403197.5	c.38C>A	p.Ala13Asp	missense_variant	2/5	2
NMNAT1	ENST00000492735.1	n.122C>A		non_coding_transcript_exon_variant	2/2	3
NMNAT1	ENST00000462686.1	c.38C>A	p.Ala13Asp	missense_variant, NMD_transcript_variant	2/6	5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1460308 Hom.: 0 Cov.: 28 AF XY: 0.00 AC XY: 0 AN XY: 726578

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Leber congenital amaurosis 9 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 23, 2023

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Ala13 amino acid residue in NMNAT1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 22842227, 22842229; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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 expected to disrupt NMNAT1 protein function. ClinVar contains an entry for this variant (Variation ID: 1376825). This missense change has been observed in individual(s) with clinical features of Leber congenital amaurosis (Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 13 of the NMNAT1 protein (p.Ala13Asp). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D;D
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D;.
M_CAP	Uncertain	0.29	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.9	.;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-5.3	D;D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0010	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	.;D
Vest4		0.96
MutPred		0.83		Gain of sheet (P = 0.1208);Gain of sheet (P = 0.1208);
MVP		0.99
MPC		0.36
ClinPred		1.0	D
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.98
gMVP		0.97

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-10032169;