dbSNP rs587777809: TTC8:c.115-2A>G (chr14-88833691-A-G) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_ModeratePM2PP5_Moderate

The NM_144596.4(TTC8):c.115-2A>G variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000616 in 1,461,264 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

TTC8
NM_144596.4 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Likely pathogenic criteria provided, single submitter P:2

Conservation

PhyloP100: 4.89

Variant links:

Genes affected

TTC8 (HGNC:20087): (tetratricopeptide repeat domain 8) This gene encodes a protein that has been directly linked to Bardet-Biedl syndrome. The primary features of this syndrome include retinal dystrophy, obesity, polydactyly, renal abnormalities and learning disabilities. Experimentation in non-human eukaryotes suggests that this gene is expressed in ciliated cells and that it is involved in the formation of cilia. A mutation in this gene has also been implicated in nonsyndromic retinitis pigmentosa. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2014]

TTC8 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.019379845 fraction of the gene. Cryptic splice site detected, with MaxEntScore 5.8, offset of -47, new splice context is: cttaggactttttattttAGaaa. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 14-88833691-A-G is Pathogenic according to our data. Variant chr14-88833691-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2532.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr14-88833691-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC8	NM_144596.4 link	c.115-2A>G		splice_acceptor_variant, intron_variant	Intron 1 of 14	ENST00000380656.7	NP_653197.2	Q8TAM2-4Q86U25

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTC8	ENST00000380656.7 link	c.115-2A>G		splice_acceptor_variant, intron_variant	Intron 1 of 14	2	NM_144596.4	ENSP00000370031.2		Q8TAM2-4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000616

AC:

AN:

1461264

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

726998

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000928

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Retinal dystrophy

Pathogenic:1

May 27, 2024

Ophthalmic Genetics Group, Institute of Molecular and Clinical Ophthalmology Basel

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Retinitis pigmentosa 51

Pathogenic:1

May 14, 2010

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.35

BayesDel_noAF

Pathogenic

0.26

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.92

FATHMM_MKL

Uncertain

0.95

GERP RS

5.8

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

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

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