rs939213590

Positions:

• chr7-16421097-G-C

Variant summary

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

The NM_001101426.4(CRPPA):​c.226C>G​(p.Leu76Val) variant causes a missense change. The variant allele was found at a frequency of 0.0000116 in 1,298,676 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000052 (0 hom.)
• Consequence: CRPPA NM_001101426.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.65

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CRPPA	NM_001101426.4	c.226C>G	p.Leu76Val	missense_variant	1/10	ENST00000407010.7	NP_001094896.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CRPPA	ENST00000407010.7	c.226C>G	p.Leu76Val	missense_variant	1/10	5	NM_001101426.4	ENSP00000385478.2
CRPPA	ENST00000399310.3	c.226C>G	p.Leu76Val	missense_variant	1/9	1		ENSP00000382249.3
CRPPA	ENST00000675257.1	c.-46-14760C>G		intron_variant				ENSP00000501664.1
CRPPA	ENST00000674759.1	c.-46-14760C>G		intron_variant				ENSP00000502749.1

Frequencies

GnomAD3 genomes AF: 0.0000592 AC: 9 AN: 152088 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000217

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 AF: 0.00000523 AC: 6 AN: 1146588 Hom.: 0 Cov.: 31 AF XY: 0.00000546 AC XY: 3 AN XY: 549628

Gnomad4 AFR exome AF: 0.000256

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: 0.0000592 AC: 9 AN: 152088 Hom.: 0 Cov.: 33 AF XY: 0.0000673 AC XY: 5 AN XY: 74300

Gnomad4 AFR AF: 0.000217

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

Alfa AF: 0.000214 Hom.: 0

Bravo AF: 0.000132

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Feb 01, 2017

- -

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7;C5190987:Autosomal recessive limb-girdle muscular dystrophy type 2U Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 24, 2021

This sequence change replaces leucine with valine at codon 76 of the ISPD protein (p.Leu76Val). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and valine. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This variant has not been reported in the literature in individuals with ISPD-related conditions. ClinVar contains an entry for this variant (Variation ID: 435528). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). 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	Benign	0.16
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.040
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Benign	0.36	T;.
Eigen	Uncertain	0.45
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.89	D;D
M_CAP	Pathogenic	0.65	D
MetaRNN	Uncertain	0.57	D;D
MetaSVM	Uncertain	0.22	D
MutationAssessor	Benign	1.2	L;L
PrimateAI	Uncertain	0.69	T
PROVEAN	Benign	-1.9	N;N
REVEL	Pathogenic	0.65
Sift	Benign	0.23	T;T
Sift4G	Benign	0.099	T;T
Polyphen		0.97	D;.
Vest4		0.47
MVP		0.76
MPC		0.12
ClinPred		0.96	D
GERP RS		4.5
Varity_R		0.73
gMVP		0.64

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: rs939213590; hg19: chr7-16460722;