7-16216064-A-C

Variant names:

• chr7-16216064-A-C
• rs370373583
• NM_001101426.4:c.1251+2T>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_001101426.4(CRPPA):​c.1251+2T>G variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.000000701 in 1,426,908 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: CRPPA NM_001101426.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 4.62
• Publications: 0 publications found

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-AS1 (HGNC:48962): (CRPPA antisense RNA 1)

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.097345136 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.3, offset of 4, new splice context is: gagGTaaaa. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CRPPA	NM_001101426.4	c.1251+2T>G		splice_donor_variant, intron_variant	Intron 9 of 9	ENST00000407010.7	NP_001094896.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CRPPA	ENST00000407010.7	c.1251+2T>G		splice_donor_variant, intron_variant	Intron 9 of 9	5	NM_001101426.4	ENSP00000385478.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.01e-7 AC: 1 AN: 1426908 Hom.: 0 Cov.: 27 AF XY: 0.00 AC XY: 0 AN XY: 710064

African (AFR) AF: 0.00 AC: 0 AN: 31464

American (AMR) AF: 0.00 AC: 0 AN: 37398

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24546

East Asian (EAS) AF: 0.00 AC: 0 AN: 39242

South Asian (SAS) AF: 0.00 AC: 0 AN: 80516

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52888

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5312

European-Non Finnish (NFE) AF: 9.12e-7 AC: 1 AN: 1096726

Other (OTH) AF: 0.00 AC: 0 AN: 58816

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.26
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Uncertain	0.92	D
PhyloP100		4.6
GERP RS		5.1
Mutation Taster		=5/95	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: 2

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

Other links and lift over

dbSNP: rs370373583; hg19: chr7-16255689;