chr22-36763918-C-A

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_001177701.3(IFT27):c.352+1G>T variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.0000586 in 1,604,688 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000062 ( 0 hom. )

Consequence

IFT27
NM_001177701.3 splice_donor, intron

Scores

Splicing: ADA: 0.9999

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 5.75

Variant links:

Genes affected

IFT27 (HGNC:18626): (intraflagellar transport 27) This gene encodes a GTP-binding protein that is a core component of the intraflagellar transport complex B. Characterization of the similar Chlamydomonas protein indicates a function in cell cycle control. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Jan 2012]

IFT27 links:

CACNG2-DT (HGNC:55682): (CACNG2 divergent transcript)

CACNG2-DT links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 22-36763918-C-A is Pathogenic according to our data. Variant chr22-36763918-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 585274.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr22-36763918-C-A is described in Lovd as [Pathogenic]. Variant chr22-36763918-C-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IFT27	NM_001177701.3 link	c.352+1G>T		splice_donor_variant, intron_variant	Intron 5 of 6	ENST00000433985.7	NP_001171172.1	Q9BW83-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IFT27	ENST00000433985.7 link	c.352+1G>T		splice_donor_variant, intron_variant	Intron 5 of 6	1	NM_001177701.3	ENSP00000393541.2		Q9BW83-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152210

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000875

AC:

AN:

251452

Hom.:

AF XY:

0.000103

AC XY:

AN XY:

135912

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000193

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000620

AC:

AN:

1452478

Hom.:

Cov.:

AF XY:

0.0000608

AC XY:

AN XY:

723356

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000788

Gnomad4 OTH exome

AF:

0.0000499

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152210

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74376

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000900

Hom.:

Bravo

AF:

0.0000567

ExAC

AF:

0.000107

AC:

EpiCase

AF:

0.000273

EpiControl

AF:

0.000296

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

IFT27-related disorder

Pathogenic:1

Oct 20, 2022

PreventionGenetics, part of Exact Sciences

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The IFT27 c.349+1G>T variant is predicted to disrupt the GT donor site and interfere with normal splicing. On an alternate transcript (NM_001177701.2), this variant is referred to as c.352+1G>T. This variant was reported in the compound heterozygous state in two individuals with features consistent with Bardet-Biedl syndrome (Schaefer et al. 2019. PubMed ID: 30761183; Quélin et al. 2018. PubMed ID: 29704304). This variant is reported in 0.019% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/22-37159962-C-A). Variants that disrupt the consensus splice donor site in IFT27 are expected to be pathogenic. This variant is interpreted as likely pathogenic. -

not provided

Pathogenic:1

Feb 03, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 5 of the IFT27 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. This variant is present in population databases (rs780659194, gnomAD 0.02%). Disruption of this splice site has been observed in individual(s) with clinical features of IFT27-related conditions (PMID: 29704304, 30761183). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as c.352+1G>T. ClinVar contains an entry for this variant (Variation ID: 585274). Studies have shown that disruption of this splice site results in skipping of exons 4-5 and 4-6, but is expected to preserve the integrity of the reading-frame (PMID: 30761183). For these reasons, this variant has been classified as Pathogenic. -

Bardet-Biedl syndrome 19

Pathogenic:1

Jul 16, 2021

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Bardet-Biedl syndrome

Pathogenic:1

Sep 15, 2018

Laboratory of Medical Genetics (UMR_S 1112), INSERM/Strasbourg University

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing;research

Mutation affecting splicing (functional study in submitter's publication) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Uncertain

0.15

BayesDel_noAF

Pathogenic

0.25

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.88

FATHMM_MKL

Uncertain

0.97

GERP RS

5.6

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.99

Position offset: 1

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over