chr7-16088333-G-A

Position:

• chr7-16088333-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BS1_Supporting

The NM_001101426.4(CRPPA):​c.*3362C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000297 in 151,722 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00030 (0 hom., cov: 32)
  • Failed GnomAD Quality Control
• Consequence: CRPPA NM_001101426.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.393

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 Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.78).
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000297 (45/151722) while in subpopulation EAS AF= 0.00852 (44/5166). AF 95% confidence interval is 0.00652. There are 0 homozygotes in gnomad4. There are 25 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRPPA	NM_001101426.4	c.*3362C>T		3_prime_UTR_variant	10/10	ENST00000407010.7
CRPPA	NM_001101417.4	c.*3362C>T		3_prime_UTR_variant	9/9
CRPPA	NM_001368197.1	c.*3362C>T		3_prime_UTR_variant	9/9
CRPPA	NR_160656.1	n.4783C>T		non_coding_transcript_exon_variant	8/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRPPA	ENST00000407010.7	c.*3362C>T		3_prime_UTR_variant	10/10	5	NM_001101426.4	P1

Frequencies

GnomAD3 genomes AF: 0.000297 AC: 45 AN: 151636 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000657

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00849

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 AC: 0 AN: 0 Hom.: 0 Cov.: 0 AC XY: 0 AN XY: 0

GnomAD4 genome AF: 0.000297 AC: 45 AN: 151722 Hom.: 0 Cov.: 32 AF XY: 0.000337 AC XY: 25 AN XY: 74104

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000656

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00852

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.000249

Asia WGS AF: 0.00144 AC: 5 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital Muscular Dystrophy, alpha-dystroglycan related Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.78
CADD	Benign	5.8
DANN	Benign	0.59

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: rs143308024; hg19: chr7-16127958;