rs751433239

Positions:

• chr3-160268405-ATACT-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_020800.3(IFT80):​c.2223+4_2223+7delAGTA variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000823 in 1,457,798 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: IFT80 NM_020800.3 splice_region, intron
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.57

Genes affected

IFT80 (HGNC:29262): (intraflagellar transport 80) The protein encoded by this gene is part of the intraflagellar transport complex B and is necessary for the function of motile and sensory cilia. Defects in this gene are a cause of asphyxiating thoracic dystrophy 2 (ATD2). Three transcript variants encoding two different isoforms have been found for this gene.[provided by RefSeq, Jun 2010]

ENSG00000248710 (HGNC:56756): (TRIM59-IFT80 readthrough (NMD candidate)) This locus represents naturally occurring readthrough transcription between the neighboring TRIM59 (tripartite motif containing 59) and IFT80 (intraflagellar transport 80) genes on chromosome 3. The readthrough transcript is unlikely to produce a protein product. [provided by RefSeq, Jun 2017]

IFT80 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Multiple lines of computational evidence support a deleterious effect 2: max_spliceai, phyloP100way_vertebrate [when was below the threshold]

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
IFT80	NM_020800.3	c.2223+4_2223+7delAGTA		splice_region_variant, intron_variant		ENST00000326448.12	NP_065851.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IFT80	ENST00000326448.12	c.2223+4_2223+7delAGTA		splice_region_variant, intron_variant		1	NM_020800.3	ENSP00000312778.7
ENSG00000248710	ENST00000483754.1	n.2736+4_2736+7delAGTA		splice_region_variant, intron_variant		2		ENSP00000456272.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000799 AC: 2 AN: 250292 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135334

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000546

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000885

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000823 AC: 12 AN: 1457798 Hom.: 0 AF XY: 0.00000689 AC XY: 5 AN XY: 725414

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000506

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000902

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Jeune thoracic dystrophy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 31, 2022

This sequence change falls in intron 19 of the IFT80 gene. It does not directly change the encoded amino acid sequence of the IFT80 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs751433239, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with IFT80-related conditions. ClinVar contains an entry for this variant (Variation ID: 528894). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: 8

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

Publications

LitVar

Other links and lift over

dbSNP: rs751433239; hg19: chr3-159986193;