rs773325665

Positions:

• chr7-16301419-A-G

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PVS1 PM2 PP3 PP5_Very_Strong

The NM_001101426.4(CRPPA):​c.835+2T>C variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000112 in 1,611,270 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.000046 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: CRPPA NM_001101426.4 splice_donor
• Scores: Splicing: ADA: 0.9888
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.48

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]

ACMG classification

Verdict is Pathogenic. Variant got 19 ACMG points.

• PVS1: Splicing variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 6.1, offset of 43, new splice context is: aatGTaagc. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, max_spliceai. No scorers claiming Uncertain. Scorers claiming Benign: dbscSNV1_RF.
• PP5: Variant 7-16301419-A-G is Pathogenic according to our data. Variant chr7-16301419-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 582317.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRPPA	NM_001101426.4	c.835+2T>C		splice_donor_variant		ENST00000407010.7
CRPPA	NM_001101417.4	c.685+2T>C		splice_donor_variant
CRPPA	NM_001368197.1	c.730+2T>C		splice_donor_variant
CRPPA	NR_160656.1	n.901-23193T>C		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRPPA	ENST00000407010.7	c.835+2T>C		splice_donor_variant		5	NM_001101426.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152154 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000145

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

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

GnomAD3 exomes AF: 0.0000162 AC: 4 AN: 247646 Hom.: 0 AF XY: 0.00000745 AC XY: 1 AN XY: 134230

Gnomad AFR exome AF: 0.000130

Gnomad AMR exome AF: 0.0000291

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000890

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000754 AC: 11 AN: 1459116 Hom.: 0 Cov.: 29 AF XY: 0.00000551 AC XY: 4 AN XY: 725800

Gnomad4 AFR exome AF: 0.0000897

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: 0.00000541

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000460 AC: 7 AN: 152154 Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3 AN XY: 74330

Gnomad4 AFR AF: 0.000145

Gnomad4 AMR AF: 0.0000655

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: 0.00000961 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.0000248 AC: 3

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Apr 24, 2019

Canonical splice site variant in a gene for which loss-of-function is a known mechanism of disease; Not observed at a significant frequency in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge -

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Dec 22, 2023

This sequence change affects a donor splice site in intron 5 of the ISPD gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in ISPD are known to be pathogenic (PMID: 23288328). This variant is present in population databases (rs773325665, gnomAD 0.01%). 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: 582317). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.30
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Benign	0.62
SpliceAI score (max)		0.93		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.54		Position offset: -41
DS_DL_spliceai		0.93		Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs773325665; hg19: chr7-16341044;