rs1554137419

Positions:

• chr5-150376424-CAA-C

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PVS1 PM2 PP3 PP5_Moderate

The NM_001371623.1(TCOF1):​c.2146_2147del​(p.Lys716ValfsTer41) variant causes a frameshift, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 34)
• Consequence: TCOF1 NM_001371623.1 frameshift, splice_region
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 2.09

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 13 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
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 5-150376424-CAA-C is Pathogenic according to our data. Variant chr5-150376424-CAA-C is described in ClinVar as [Pathogenic]. Clinvar id is 477615.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr5-150376424-CAA-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TCOF1	NM_001371623.1	c.2146_2147del	p.Lys716ValfsTer41	frameshift_variant, splice_region_variant	14/27	ENST00000643257.2	NP_001358552.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TCOF1	ENST00000643257.2	c.2146_2147del	p.Lys716ValfsTer41	frameshift_variant, splice_region_variant	14/27		NM_001371623.1	ENSP00000493815	P3

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

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Treacher Collins syndrome 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 01, 2022

Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 477615). This variant is also known as c.1915_1916delAA. This premature translational stop signal has been observed in individual(s) with Treacher Collins syndrome (PMID: 15150774). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Lys716Valfs*41) in the TCOF1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TCOF1 are known to be pathogenic (PMID: 8894686, 22317976). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.60		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.60		Position offset: 5

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

Publications

LitVar

Other links and lift over

dbSNP: rs1554137419; hg19: chr5-149755987;