Genetic Variant NAPB:p.His79Pro (chr20-23397131-T-G) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2PP3

The NM_022080.3(NAPB):c.236A>C(p.His79Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,506 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. H79R) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

NAPB
NM_022080.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 8.01

Publications

0 publications found

Variant links:

Genes affected

NAPB (HGNC:15751): (NSF attachment protein beta) This gene encodes a member of the soluble N-ethyl-maleimide-sensitive fusion attachment protein (SNAP) family. SNAP proteins play a critical role in the docking and fusion of vesicles to target membranes as part of the 20S NSF-SNAP-SNARE complex. This gene encodes the SNAP beta isoform which has been shown to be preferentially expressed in brain tissue. The encoded protein also interacts with the GluR2 α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor subunit C-terminus and may play a role as a chaperone in the molecular processing of the AMPA receptor. [provided by RefSeq, Mar 2017]

NAPB Gene-Disease associations (from GenCC):

developmental and epileptic encephalopathy 107
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P

NAPB links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.749

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NAPB	NM_022080.3 link	c.236A>C	p.His79Pro	missense_variant	Exon 3 of 11	ENST00000377026.4	NP_071363.1	Q9H115-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NAPB	ENST00000377026.4 link	c.236A>C	p.His79Pro	missense_variant	Exon 3 of 11	1	NM_022080.3	ENSP00000366225.4		Q9H115-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461506

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727050

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:

33470

American (AMR)

AF:

0.00

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39686

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86238

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111722

Other (OTH)

AF:

0.00

AC:

AN:

60376

⚠️ 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: 0.325

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

AlphaMissense

Pathogenic

0.86

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Uncertain

0.060

CADD

Pathogenic

(source)

DANN

Benign

0.96

DEOGEN2

Benign

0.33

.;T

Eigen

Uncertain

0.31

Eigen_PC

Uncertain

0.43

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.94

D;D

M_CAP

Benign

0.038

MetaRNN

Pathogenic

0.75

D;D

MetaSVM

Uncertain

-0.28

PhyloP100

8.0

PrimateAI

Pathogenic

0.90

PROVEAN

Pathogenic

-9.0

.;D

REVEL

Uncertain

0.55

Sift

Uncertain

0.019

.;D

Sift4G

Uncertain

0.022

D;D

Polyphen

0.97

.;D

Vest4

0.75

MutPred

0.44

.;Loss of helix (P = 0.028);

MVP

0.35

MPC

1.4

ClinPred

1.0

GERP RS

5.6

Varity_R

0.93

gMVP

0.86

Mutation Taster

=79/121

disease causing

(source)

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