rs368593151

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_001101426.4(CRPPA):​c.802C>T​(p.Arg268*) variant causes a stop gained change. The variant allele was found at a frequency of 0.0000174 in 1,612,072 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 Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

CRPPA
NM_001101426.4 stop_gained

Scores

4
2
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 3.96

Publications

5 publications found
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 Gene-Disease associations (from GenCC):
  • muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
  • myopathy caused by variation in CRPPA
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
  • autosomal recessive limb-girdle muscular dystrophy type 2U
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • congenital muscular dystrophy without intellectual disability
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • muscular dystrophy-dystroglycanopathy, type A
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 7-16301454-G-A is Pathogenic according to our data. Variant chr7-16301454-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 31568.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CRPPANM_001101426.4 linkc.802C>T p.Arg268* stop_gained Exon 5 of 10 ENST00000407010.7 NP_001094896.1 A4D126-1
CRPPANM_001368197.1 linkc.697C>T p.Arg233* stop_gained Exon 4 of 9 NP_001355126.1
CRPPANM_001101417.4 linkc.652C>T p.Arg218* stop_gained Exon 4 of 9 NP_001094887.1 A4D126-2A0A140VJM1
CRPPANR_160656.1 linkn.901-23228C>T intron_variant Intron 3 of 7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CRPPAENST00000407010.7 linkc.802C>T p.Arg268* stop_gained Exon 5 of 10 5 NM_001101426.4 ENSP00000385478.2 A4D126-1

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152122
Hom.:
0
Cov.:
32
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000403
AC:
1
AN:
247882
AF XY:
0.00000744
show subpopulations
Gnomad AFR exome
AF:
0.0000649
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000171
AC:
25
AN:
1459950
Hom.:
0
Cov.:
29
AF XY:
0.0000110
AC XY:
8
AN XY:
726202
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33454
American (AMR)
AF:
0.00
AC:
0
AN:
44668
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26110
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39664
South Asian (SAS)
AF:
0.00
AC:
0
AN:
85884
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53380
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5764
European-Non Finnish (NFE)
AF:
0.0000207
AC:
23
AN:
1110704
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60322
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.453
Heterozygous variant carriers
0
1
3
4
6
7
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000197
AC:
3
AN:
152122
Hom.:
0
Cov.:
32
AF XY:
0.0000269
AC XY:
2
AN XY:
74308
show subpopulations
African (AFR)
AF:
0.0000241
AC:
1
AN:
41422
American (AMR)
AF:
0.00
AC:
0
AN:
15274
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3466
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5180
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10606
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68026
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.508
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.0000189
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000122
AC:
1
ExAC
AF:
0.00000828
AC:
1

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Pathogenic:2
Dec 04, 2018
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The R268X nonsense variant in the ISPD gene has been reported previously in an individual with muscle-eye-brain disease who had a second variant identified on the opposite ISPD allele (in trans) (Roscioli et al., 2012). The R268X variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016). This pathogenic variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. -

Jun 01, 2018
Eurofins Ntd Llc (ga)
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7 Pathogenic:1
May 01, 2012
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7;C5190987:Autosomal recessive limb-girdle muscular dystrophy type 2U Pathogenic:1
Oct 21, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Arg268*) in the ISPD gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ISPD are known to be pathogenic (PMID: 23288328). This variant is present in population databases (rs368593151, gnomAD 0.007%). This premature translational stop signal has been observed in individual(s) with muscle eye brain disease (PMID: 22522421). ClinVar contains an entry for this variant (Variation ID: 31568). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.50
D
BayesDel_noAF
Pathogenic
0.60
CADD
Pathogenic
48
DANN
Uncertain
1.0
Eigen
Pathogenic
0.85
Eigen_PC
Pathogenic
0.72
FATHMM_MKL
Uncertain
0.94
D
PhyloP100
4.0
Vest4
0.91
GERP RS
5.2
Mutation Taster
=2/198
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.33
Details are displayed if max score is > 0.2
DS_AL_spliceai
0.33
Position offset: 12

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

Publications

Other links and lift over

dbSNP: rs368593151; hg19: chr7-16341079; API