chr7-16087603-T-C

Position:

• chr7-16087603-T-C

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BS1_Supporting BS2

The NM_001101426.4(CRPPA):​c.*4092A>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00227 in 152,100 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0023 (2 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: 1.34

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 Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).
• BS1: Variant frequency is greater than expected in population amr. gnomad4 allele frequency = 0.00227 (345/152100) while in subpopulation AMR AF= 0.00557 (85/15274). AF 95% confidence interval is 0.00461. There are 2 homozygotes in gnomad4. There are 180 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
• BS2: High Homozygotes in GnomAd4 at 2 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRPPA	NM_001101426.4	c.*4092A>G		3_prime_UTR_variant	10/10	ENST00000407010.7
CRPPA	NM_001101417.4	c.*4092A>G		3_prime_UTR_variant	9/9
CRPPA	NM_001368197.1	c.*4092A>G		3_prime_UTR_variant	9/9
CRPPA	NR_160656.1	n.5513A>G		non_coding_transcript_exon_variant	8/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRPPA	ENST00000407010.7	c.*4092A>G		3_prime_UTR_variant	10/10	5	NM_001101426.4	P1

Frequencies

GnomAD3 genomes AF: 0.00227 AC: 345 AN: 151986 Hom.: 2 Cov.: 32

Gnomad AFR AF: 0.00364

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00557

Gnomad ASJ AF: 0.00115

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00949

Gnomad NFE AF: 0.00124

Gnomad OTH AF: 0.00860

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: 0.00227 AC: 345 AN: 152100 Hom.: 2 Cov.: 32 AF XY: 0.00242 AC XY: 180 AN XY: 74360

Gnomad4 AFR AF: 0.00363

Gnomad4 AMR AF: 0.00557

Gnomad4 ASJ AF: 0.00115

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00124

Gnomad4 OTH AF: 0.00852

Alfa AF: 0.000265 Hom.: 0

Bravo AF: 0.00294

Asia WGS AF: 0.000291 AC: 1 AN: 3448

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	-0.83
CADD	Benign	9.3
DANN	Benign	0.76

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: rs188823385; hg19: chr7-16127228;