8-68027289-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_024870.4(PREX2):c.509T>C(p.Ile170Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,610,450 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: PREX2 NM_024870.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.52

Genes affected

PREX2 (HGNC:22950): (phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 2) The protein encoded by this gene belongs to the phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger (PREX) family, which are Dbl-type guanine-nucleotide exchange factors for Rac family small G proteins. Structural domains of this protein include the catalytic diffuse B-cell lymphoma homology and pleckstrin homology (DHPH) domain, two disheveled, EGL-10, and pleckstrin homology (DEP) domains, two PDZ domains, and a C-terminal inositol polyphosphate-4 phosphatase (IP4P) domain that is found in one of the isoforms. This protein facilitates the exchange of GDP for GTP on Rac1, allowing the GTP-bound Rac1 to activate downstream effectors. Studies also show that the pleckstrin homology domain of this protein interacts with the phosphatase and tensin homolog (PTEN) gene product to inhibit PTEN phosphatase activity, thus activating the phosphoinositide-3 kinase (PI3K) signaling pathway. Conversely, the PTEN gene product has also been shown to inhibit the GEF activity of this protein. This gene plays a role in insulin-signaling pathways, and either mutations or overexpression of this gene have been observed in some cancers. [provided by RefSeq, Apr 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.932

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PREX2	NM_024870.4	c.509T>C	p.Ile170Thr	missense_variant	5/40	ENST00000288368.5
PREX2	NM_025170.6	c.509T>C	p.Ile170Thr	missense_variant	5/24
PREX2	XM_047422267.1	c.374T>C	p.Ile125Thr	missense_variant	5/40
PREX2	XM_047422268.1	c.509T>C	p.Ile170Thr	missense_variant	5/28

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PREX2	ENST00000288368.5	c.509T>C	p.Ile170Thr	missense_variant	5/40	1	NM_024870.4	P1
PREX2	ENST00000529398.5	n.536T>C		non_coding_transcript_exon_variant	5/24	1
PREX2	ENST00000517617.1	n.220T>C		non_coding_transcript_exon_variant	3/24	2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152076 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1458374 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 725650

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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 AF: 0.00000658 AC: 1 AN: 152076 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74304

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000656

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 21, 2021

The c.509T>C (p.I170T) alteration is located in exon 5 (coding exon 5) of the PREX2 gene. This alteration results from a T to C substitution at nucleotide position 509, causing the isoleucine (I) at amino acid position 170 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
Cadd	Pathogenic	28
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.42	T
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Uncertain	0.29	D
MutationAssessor	Uncertain	2.9	M
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.72
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.71		Gain of phosphorylation at I170 (P = 0.0786);
MVP		0.85
MPC		1.5
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.72
gMVP		0.61

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs1807752891; hg19: chr8-68939524;