NM_001371623.1:c.1448_1451delACAG

Variant names:

• chr5-150375119-TCAGA-T
• rs1064794474
• NM_001371623.1:c.1448_1451delACAG

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001371623.1(TCOF1):​c.1448_1451delACAG​(p.Asp483ValfsTer9) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 34)
• Consequence: TCOF1 NM_001371623.1 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 2.39

Genes affected

TCOF1 (HGNC:11654): (treacle ribosome biogenesis factor 1) This gene encodes a nucleolar protein with a LIS1 homology domain. The protein is involved in ribosomal DNA gene transcription through its interaction with upstream binding factor (UBF). Mutations in this gene have been associated with Treacher Collins syndrome, a disorder which includes abnormal craniofacial development. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2008]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 5-150375119-TCAGA-T is Pathogenic according to our data. Variant chr5-150375119-TCAGA-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 420429.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCOF1	NM_001371623.1	c.1448_1451delACAG	p.Asp483ValfsTer9	frameshift_variant	Exon 10 of 27	ENST00000643257.2	NP_001358552.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TCOF1	ENST00000643257.2	c.1448_1451delACAG	p.Asp483ValfsTer9	frameshift_variant	Exon 10 of 27		NM_001371623.1	ENSP00000493815.1

Frequencies

GnomAD3 genomes Cov.: 34

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Treacher Collins syndrome 1 Pathogenic:2

May 16, 2018

Autoinflammatory diseases unit, CHU de Montpellier

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Nov 14, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Asp483Valfs*9) in the TCOF1 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with TCOF1-related disease. ClinVar contains an entry for this variant (Variation ID: 420429). Loss-of-function variants in TCOF1 are known to be pathogenic (PMID: 8894686, 22317976). For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Jan 25, 2016

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1448_1451delACAG likely pathogenic variant in the TCOF1 gene causes a frameshift starting with codon Aspartic acid 483, changes this amino acid to a Valine residue and creates a premature Stop codon at position 9 of the new reading frame, denoted p.Asp483ValfsX9. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. In addition, the c.1448_1451delACAG variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Although c.1448_1451delACAG has not been previously reported to our knowledge, this variant is likely pathogenic; however, the possibility that it is benign cannot be excluded. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1064794474; hg19: chr5-149754682;