rs772784211

chr3-33114208-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_006371.5(CRTAP):c.131T>C(p.Leu44Pro) variant causes a missense change. The variant allele was found at a frequency of 0.00000694 in 1,441,804 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. L44L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000069 (0 hom.)
• Consequence: CRTAP NM_006371.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.73

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRTAP	NM_006371.5	c.131T>C	p.Leu44Pro	missense_variant	1/7	ENST00000320954.11
CRTAP	NM_001393363.1	c.131T>C	p.Leu44Pro	missense_variant	1/6
CRTAP	NM_001393364.1	c.131T>C	p.Leu44Pro	missense_variant	1/6
CRTAP	NM_001393365.1	c.131T>C	p.Leu44Pro	missense_variant	1/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRTAP	ENST00000320954.11	c.131T>C	p.Leu44Pro	missense_variant	1/7	1	NM_006371.5	P1
CRTAP	ENST00000449224.1	c.131T>C	p.Leu44Pro	missense_variant	1/6	2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.0000706 AC: 15 AN: 212530 Hom.: 0 AF XY: 0.0000676 AC XY: 8 AN XY: 118392

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000894

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000694 AC: 10 AN: 1441804 Hom.: 0 Cov.: 32 AF XY: 0.00000697 AC XY: 5 AN XY: 717260

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000230

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000167

GnomAD4 genome Cov.: 34

Bravo AF: 0.00000378

ExAC AF: 0.0000424 AC: 5

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 15, 2023

The c.131T>C (p.L44P) alteration is located in exon 1 (coding exon 1) of the CRTAP gene. This alteration results from a T to C substitution at nucleotide position 131, causing the leucine (L) at amino acid position 44 to be replaced by a proline (P). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Osteogenesis imperfecta type 7 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 21, 2017

This sequence change replaces leucine with proline at codon 44 of the CRTAP protein (p.Leu44Pro). The leucine residue is highly conserved and there is a moderate physicochemical difference between leucine and proline. This variant is present in population databases (rs772784211, ExAC 0.09%). This variant has not been reported in the literature in individuals with CRTAP-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Benign	-0.057	T
BayesDel_noAF	Uncertain	0.080
Cadd	Pathogenic	30
Dann	Uncertain	0.99
DEOGEN2	Benign	0.30	T;T
Eigen	Benign	0.064
Eigen_PC	Benign	-0.024
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.92	D;D
M_CAP	Uncertain	0.17	D
MetaRNN	Uncertain	0.60	D;D
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	2.0	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.0	D;D
REVEL	Uncertain	0.34
Sift	Benign	0.070	T;D
Sift4G	Uncertain	0.054	T;T
Polyphen		1.0	D;D
Vest4		0.88
MutPred		0.51		Gain of glycosylation at Y48 (P = 0.0116);Gain of glycosylation at Y48 (P = 0.0116);
MVP		0.49
MPC		0.71
ClinPred		0.35	T
GERP RS		2.0
Varity_R		0.74
gMVP		0.94

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: rs772784211; hg19: chr3-33155700;