rs142073418

Variant summary

Our verdict is Benign. Variant got -13 ACMG points: 2P and 15B. PM2BP4_ModerateBP6_Very_StrongBP7BS1

The NM_144596.4(TTC8):c.1464G>A(p.Ala488=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000279 in 1,613,404 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. A488A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

TTC8
NM_144596.4 synonymous

Scores

Clinical Significance

Likely benign criteria provided, multiple submitters, no conflicts B:3

Conservation

PhyloP100: -0.0970

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -13 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.42).

BP6

Variant 14-88877326-G-A is Benign according to our data. Variant chr14-88877326-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 1627334.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-0.097 with no splicing effect.

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000112 (17/151964) while in subpopulation AFR AF= 0.000411 (17/41370). AF 95% confidence interval is 0.000261. There are 0 homozygotes in gnomad4. There are 8 alleles in male gnomad4 subpopulation. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTC8	NM_144596.4 linkuse as main transcript	c.1464G>A	p.Ala488=	synonymous_variant	15/15	ENST00000380656.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTC8	ENST00000380656.7 linkuse as main transcript	c.1464G>A	p.Ala488=	synonymous_variant	15/15	2	NM_144596.4		Q8TAM2-4

Frequencies

GnomAD3 genomes

AF:

0.000112

AC:

AN:

151964

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000411

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000319

AC:

AN:

250616

Hom.:

AF XY:

0.0000295

AC XY:

AN XY:

135414

show subpopulations

Gnomad AFR exome

AF:

0.000492

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000192

AC:

AN:

1461440

Hom.:

Cov.:

AF XY:

0.0000165

AC XY:

AN XY:

727012

show subpopulations

Gnomad4 AFR exome

AF:

0.000448

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:

0.00000899

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.000112

AC:

AN:

151964

Hom.:

Cov.:

AF XY:

0.000108

AC XY:

AN XY:

74194

show subpopulations

Gnomad4 AFR

AF:

0.000411

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:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.000140

ClinVar

Significance: Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Bardet-Biedl syndrome 8;C3150715:Retinitis pigmentosa 51

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Feb 12, 2022

- -

TTC8-related disorder

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 26, 2020

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Bardet-Biedl syndrome

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Nov 01, 2022

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.42

Cadd

Benign

9.2

Dann

Benign

0.55

Splicing

Name

Calibrated prediction

Score

Prediction

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