Genetic Variant CRPPA:p.Pro65Thr (chr7-16421130-G-T) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_001101426.4(CRPPA):c.193C>A(p.Pro65Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000658 in 152,056 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: 33)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

CRPPA
NM_001101426.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 6.65

Variant links:

Genes affected

CRPPA (HGNC:37276): (CDP-L-ribitol pyrophosphorylase A) This gene encodes a 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase-like protein. Mutations in this gene are the cause of Walker-Warburg syndrome. Alternate splicing results in multiple transcript variants. [provided by RefSeq, May 2012]

CRPPA links:

LOC105375168 (HGNC:):

LOC105375168 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

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, 0.908

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CRPPA	NM_001101426.4 link	c.193C>A	p.Pro65Thr	missense_variant	Exon 1 of 10	ENST00000407010.7	NP_001094896.1	A4D126-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
CRPPA	ENST00000407010.7 link	c.193C>A	p.Pro65Thr	missense_variant	Exon 1 of 10	5	NM_001101426.4	ENSP00000385478.2	A4D126-1
CRPPA	ENST00000399310.3 link	c.193C>A	p.Pro65Thr	missense_variant	Exon 1 of 9	1		ENSP00000382249.3	A4D126-2
CRPPA	ENST00000675257.1 link	c.-46-14793C>A		intron_variant	Intron 2 of 9			ENSP00000501664.1	A0A6Q8PF75
CRPPA	ENST00000674759.1 link	c.-46-14793C>A		intron_variant	Intron 2 of 9			ENSP00000502749.1	A0A6Q8PHI3

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152056

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1175846

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

566854

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

AF:

0.00000658

AC:

AN:

152056

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74264

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

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:

0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 29, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.193C>A (p.P65T) alteration is located in exon 1 (coding exon 1) of the ISPD gene. This alteration results from a C to A substitution at nucleotide position 193, causing the proline (P) at amino acid position 65 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Mar 21, 2023

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7;C5190987:Autosomal recessive limb-girdle muscular dystrophy type 2U

Uncertain:1

Oct 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 65 of the ISPD protein (p.Pro65Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ISPD-related conditions. ClinVar contains an entry for this variant (Variation ID: 579387). 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 ISPD protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.71

BayesDel_addAF

Pathogenic

0.32

BayesDel_noAF

Pathogenic

0.23

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.77

D;.

Eigen

Pathogenic

0.70

Eigen_PC

Uncertain

0.64

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.90

D;D

M_CAP

Pathogenic

0.91

MetaRNN

Pathogenic

0.91

D;D

MetaSVM

Pathogenic

0.87

MutationAssessor

Pathogenic

3.9

H;H

PrimateAI

Pathogenic

0.87

PROVEAN

Pathogenic

-6.6

D;D

REVEL

Pathogenic

0.87

Sift

Uncertain

0.016

D;D

Sift4G

Uncertain

0.0050

D;D

Polyphen

1.0

D;.

Vest4

0.64

MutPred

0.74

Loss of glycosylation at P65 (P = 0.0394);Loss of glycosylation at P65 (P = 0.0394);

MVP

0.71

MPC

0.37

ClinPred

1.0

GERP RS

4.2

Varity_R

0.93

gMVP

0.75

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over