rs768012717

chr3-33114220-A-Gchr3-33114220-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_006371.5(CRTAP):c.143A>G(p.Tyr48Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000565 in 1,592,862 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y48F) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 34)
  • Exomes 𝑓: 0.0000056 (0 hom.)
• Consequence: CRTAP NM_006371.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.97

Genes affected

CRTAP (HGNC:2379): (cartilage associated protein) The protein encoded by this gene is similar to the chicken and mouse CRTAP genes. The encoded protein is a scaffolding protein that may influence the activity of at least one member of the cytohesin/ARNO family in response to specific cellular stimuli. Defects in this gene are associated with osteogenesis imperfecta, a connective tissue disorder characterized by bone fragility and low bone mass. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.925

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRTAP	NM_006371.5	c.143A>G	p.Tyr48Cys	missense_variant	1/7	ENST00000320954.11
CRTAP	NM_001393363.1	c.143A>G	p.Tyr48Cys	missense_variant	1/6
CRTAP	NM_001393364.1	c.143A>G	p.Tyr48Cys	missense_variant	1/6
CRTAP	NM_001393365.1	c.143A>G	p.Tyr48Cys	missense_variant	1/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRTAP	ENST00000320954.11	c.143A>G	p.Tyr48Cys	missense_variant	1/7	1	NM_006371.5	P1
CRTAP	ENST00000449224.1	c.143A>G	p.Tyr48Cys	missense_variant	1/6	2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152034 Hom.: 0 Cov.: 34

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: 0.00000555 AC: 8 AN: 1440828 Hom.: 0 Cov.: 32 AF XY: 0.00000419 AC XY: 3 AN XY: 716550

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000722

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152034 Hom.: 0 Cov.: 34 AF XY: 0.0000135 AC XY: 1 AN XY: 74284

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Osteogenesis imperfecta type 7 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 30, 2021	This sequence change replaces tyrosine with cysteine at codon 48 of the CRTAP protein (p.Tyr48Cys). The tyrosine residue is highly conserved and there is a large physicochemical difference between tyrosine and cysteine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with CRTAP-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 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
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.37
Cadd	Pathogenic	32
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D;T
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.82	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Uncertain	0.30	D
MutationAssessor	Pathogenic	3.2	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.7	D;D
REVEL	Pathogenic	0.84
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.95
MutPred		0.61		Gain of glycosylation at Y48 (P = 0.0116);Gain of glycosylation at Y48 (P = 0.0116);
MVP		0.94
MPC		0.62
ClinPred		1.0	D
GERP RS		3.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.89
gMVP		0.92

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: rs768012717; hg19: chr3-33155712;