3-33146339-C-A

Variant names:

• chr3-33146339-C-A
• rs4678478
• NM_006371.5:c.*3891C>A

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_Strong BS1_Supporting BS2

The NM_006371.5(CRTAP):​c.*3891C>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00282 in 152,336 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 0.0028 (2 hom., cov: 33)
  • Exomes 𝑓: 0.0072 (0 hom.)
• Consequence: CRTAP NM_006371.5 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0330
• Publications: 5 publications found

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]

CRTAP Gene-Disease associations (from GenCC):

• osteogenesis imperfecta type 7

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• osteogenesis imperfecta type 2

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• osteogenesis imperfecta type 3

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• osteogenesis imperfecta type 4

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000272149 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.67).
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00282 (429/152198) while in subpopulation AFR AF = 0.00984 (409/41552). AF 95% confidence interval is 0.00906. There are 2 homozygotes in GnomAd4. There are 199 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High Homozygotes in GnomAd4 at 2 AR,AD gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CRTAP	NM_006371.5	c.*3891C>A		3_prime_UTR_variant	Exon 7 of 7	ENST00000320954.11	NP_006362.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CRTAP	ENST00000320954.11	c.*3891C>A		3_prime_UTR_variant	Exon 7 of 7	1	NM_006371.5	ENSP00000323696.5
ENSG00000272149	ENST00000607832.1	n.166+1217G>T		intron_variant	Intron 1 of 1	3

Frequencies

GnomAD3 genomes AF: 0.00281 AC: 427 AN: 152080 Hom.: 2 Cov.: 33

Gnomad AFR AF: 0.00982

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00335

GnomAD4 exome AF: 0.00725 AC: 1 AN: 138 Hom.: 0 Cov.: 0 AF XY: 0.00962 AC XY: 1 AN XY: 104

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

African (AFR) AF: 0.250 AC: 1 AN: 4

American (AMR) AF: 0.00 AC: 0 AN: 2

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 2

East Asian (EAS) AF: 0.00 AC: 0 AN: 6

South Asian (SAS) AC: 0 AN: 0

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 4

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 2

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 102

Other (OTH) AF: 0.00 AC: 0 AN: 16

⚠️ 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: 0.00282 AC: 429 AN: 152198 Hom.: 2 Cov.: 33 AF XY: 0.00267 AC XY: 199 AN XY: 74402

African (AFR) AF: 0.00984 AC: 409 AN: 41552

American (AMR) AF: 0.000654 AC: 10 AN: 15298

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5148

South Asian (SAS) AF: 0.000207 AC: 1 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10572

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68018

Other (OTH) AF: 0.00332 AC: 7 AN: 2110

Alfa AF: 0.00 Hom.: 4996

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Osteogenesis imperfecta type 7 Uncertain:1

Apr 28, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.67
CADD	Benign	6.0
DANN	Benign	0.84
PhyloP100		0.033
Mutation Taster		=100/0	polymorphism

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

Other links and lift over

dbSNP: rs4678478; hg19: chr3-33187831;