7-16301454-G-C

Variant names:

• chr7-16301454-G-C
• rs368593151
• NM_001101426.4:c.802C>G
• CRPPA p.Arg268Gly

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001101426.4(CRPPA):​c.802C>G​(p.Arg268Gly) variant causes a missense change. The variant allele was found at a frequency of 0.00000124 in 1,612,072 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R268Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CRPPA NM_001101426.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.96
• Publications: 5 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 Gene-Disease associations (from GenCC):

• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
• 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

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.774

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001101426.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRPPA	NM_001101426.4	MANE Select	c.802C>G	p.Arg268Gly	missense	Exon 5 of 10	NP_001094896.1	A4D126-1
	CRPPA	NM_001368197.1		c.697C>G	p.Arg233Gly	missense	Exon 4 of 9	NP_001355126.1
	CRPPA	NM_001101417.4		c.652C>G	p.Arg218Gly	missense	Exon 4 of 9	NP_001094887.1	A0A140VJM1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRPPA	ENST00000407010.7	TSL:5 MANE Select	c.802C>G	p.Arg268Gly	missense	Exon 5 of 10	ENSP00000385478.2	A4D126-1
	CRPPA	ENST00000399310.3	TSL:1	c.652C>G	p.Arg218Gly	missense	Exon 4 of 9	ENSP00000382249.3	A4D126-2
	CRPPA	ENST00000856526.1		c.802C>G	p.Arg268Gly	missense	Exon 5 of 8	ENSP00000526585.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152122 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459950 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 726202

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

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: 0.00 AC: 0 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: 0.000173 AC: 1 AN: 5764

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1110704

Other (OTH) AF: 0.00 AC: 0 AN: 60322

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152122 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74308

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 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: 0.0000147 AC: 1 AN: 68026

Other (OTH) AF: 0.00 AC: 0 AN: 2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Uncertain	0.083	D
BayesDel_noAF	Benign	-0.12
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.56	D
Eigen	Uncertain	0.41
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.82	T
M_CAP	Benign	0.043	D
MetaRNN	Pathogenic	0.77	D
MetaSVM	Uncertain	0.19	D
MutationAssessor	Benign	1.6	L
PhyloP100		4.0
PrimateAI	Benign	0.33	T
PROVEAN	Uncertain	-3.9	D
REVEL	Uncertain	0.49
Sift	Uncertain	0.0070	D
Sift4G	Benign	0.34	T
Varity_R		0.70
gMVP		0.62
Mutation Taster		=57/43	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs368593151;

hg19: chr7-16341079;

COSMIC: COSV101235396;