18-26856350-A-T

Position:

• chr18-26856350-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001650.7(AQP4):​c.833T>A​(p.Met278Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 33)
• Consequence: AQP4 NM_001650.7 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.54

Genes affected

AQP4 (HGNC:637): (aquaporin 4) This gene encodes a member of the aquaporin family of intrinsic membrane proteins that function as water-selective channels in the plasma membranes of many cells. This protein is the predominant aquaporin found in brain and has an important role in brain water homeostasis. Alternatively spliced transcript variants encoding different isoforms have been described for this gene. Additional isoforms, resulting from the use of alternative in-frame translation initiation codons, have also been described. Recent studies provided evidence for translational readthrough in this gene, and expression of C-terminally extended isoforms via the use of an alternative in-frame translation termination codon. [provided by RefSeq, Jun 2018]

AQP4-AS1 (HGNC:26399): (AQP4 antisense RNA 1)

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.08793697).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
AQP4	NM_001650.7	c.833T>A	p.Met278Lys	missense_variant	5/5	ENST00000383168.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
AQP4	ENST00000383168.9	c.833T>A	p.Met278Lys	missense_variant	5/5	1	NM_001650.7	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.071
BayesDel_addAF	Benign	-0.020	T
BayesDel_noAF	Benign	-0.27
CADD	Benign	20
DANN	Benign	0.82
DEOGEN2	Benign	0.27	T;.;.
Eigen	Benign	-0.40
Eigen_PC	Benign	-0.13
FATHMM_MKL	Benign	0.72	D
LIST_S2	Benign	0.76	T;.;T
M_CAP	Benign	0.0089	T
MetaRNN	Benign	0.088	T;T;T
MetaSVM	Benign	-0.86	T
MutationAssessor	Benign	0.76	N;.;.
MutationTaster	Benign	0.91	N;N;N
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-0.17	N;.;.
REVEL	Benign	0.24
Sift	Benign	0.79	T;.;.
Sift4G	Benign	0.92	T;T;T
Polyphen		0.0	B;.;.
Vest4		0.17
MutPred		0.48		Gain of ubiquitination at M278 (P = 0.0022);.;.;
MVP		0.87
MPC		0.20
ClinPred		0.17	T
GERP RS		5.8
Varity_R		0.45
gMVP		0.41

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs3906956; hg19: chr18-24436314; COSMIC: COSV67218198; COSMIC: COSV67218198;