2-208271544-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_015040.4(PIKFYVE):c.25C>T(p.Pro9Ser) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PIKFYVE NM_015040.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.80

Genes affected

PIKFYVE (HGNC:23785): (phosphoinositide kinase, FYVE-type zinc finger containing) Phosphorylated derivatives of phosphatidylinositol (PtdIns) regulate cytoskeletal functions, membrane trafficking, and receptor signaling by recruiting protein complexes to cell- and endosomal-membranes. Humans have multiple PtdIns proteins that differ by the degree and position of phosphorylation of the inositol ring. This gene encodes an enzyme (PIKfyve; also known as phosphatidylinositol-3-phosphate 5-kinase type III or PIPKIII) that phosphorylates the D-5 position in PtdIns and phosphatidylinositol-3-phosphate (PtdIns3P) to make PtdIns5P and PtdIns(3,5)biphosphate. The D-5 position also can be phosphorylated by type I PtdIns4P-5-kinases (PIP5Ks) that are encoded by distinct genes and preferentially phosphorylate D-4 phosphorylated PtdIns. In contrast, PIKfyve preferentially phosphorylates D-3 phosphorylated PtdIns. In addition to being a lipid kinase, PIKfyve also has protein kinase activity. PIKfyve regulates endomembrane homeostasis and plays a role in the biogenesis of endosome carrier vesicles from early endosomes. The protein plays a key role in cell entry of ebola virus and SARS-CoV-2 by endocytosis Mutations in this gene cause corneal fleck dystrophy (CFD); an autosomal dominant disorder characterized by numerous small white flecks present in all layers of the corneal stroma. Histologically, these flecks appear to be keratocytes distended with lipid and mucopolysaccharide filled intracytoplasmic vacuoles. [provided by RefSeq, Jul 2021]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, PIKFYVE
• BP4: Computational evidence support a benign effect (MetaRNN=0.11427194).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PIKFYVE	NM_015040.4	c.25C>T	p.Pro9Ser	missense_variant	2/42	ENST00000264380.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PIKFYVE	ENST00000264380.9	c.25C>T	p.Pro9Ser	missense_variant	2/42	1	NM_015040.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Fleck corneal dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.013	T
BayesDel_noAF	Benign	-0.26
Cadd	Benign	19
Dann	Pathogenic	1.0
Eigen	Benign	-0.21
Eigen_PC	Benign	0.017
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.91	D;D;D;D;D;D
M_CAP	Benign	0.0047	T
MetaRNN	Benign	0.11	T;T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.81	L;L;L;L;.;.
MutationTaster	Benign	0.95	D;D;N;N
PrimateAI	Benign	0.47	T
PROVEAN	Benign	-1.6	N;N;N;N;N;N
REVEL	Benign	0.057
Sift	Benign	0.21	T;D;T;T;T;T
Sift4G	Benign	0.89	T;T;T;T;T;T
Polyphen		0.015	B;B;.;B;.;B
Vest4		0.16
MutPred		0.13		Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);
MVP		0.46
MPC		0.29
ClinPred		0.60	D
GERP RS		5.2
Varity_R		0.19
gMVP		0.23

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

LitVar

Other links and lift over

dbSNP: rs1689422489; hg19: chr2-209136268; COSMIC: COSV52249776; COSMIC: COSV52249776;