Submissions for variant NM_144596.4(TTC8):c.1327C>T (p.Arg443Trp)

gnomAD frequency: 0.00064  dbSNP: rs140698625

Total submissions: 8

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
Labcorp Genetics (formerly Invitae), Labcorp	RCV000638366	SCV000759865	uncertain significance	Bardet-Biedl syndrome	2024-01-19	criteria provided, single submitter	clinical testing	This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 433 of the TTC8 protein (p.Arg433Trp). This variant is present in population databases (rs140698625, gnomAD 0.2%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with clinical features of inherited retinal disease (PMID: 25097241, 30718709, 33964006). This variant is also known as c.C733T, p.R245W. ClinVar contains an entry for this variant (Variation ID: 531831). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt TTC8 protein function with a negative predictive value of 80%. 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.
Fulgent Genetics, Fulgent Genetics	RCV000765185	SCV000896420	uncertain significance	Retinitis pigmentosa 51; Bardet-Biedl syndrome 8	2018-10-31	criteria provided, single submitter	clinical testing
Illumina Laboratory Services, Illumina	RCV001117718	SCV001275936	uncertain significance	Retinitis pigmentosa	2018-01-13	criteria provided, single submitter	clinical testing	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease.
Illumina Laboratory Services, Illumina	RCV001117719	SCV001275937	uncertain significance	Bardet-Biedl syndrome 8	2018-01-13	criteria provided, single submitter	clinical testing	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease.
New York Genome Center	RCV001117719	SCV002764441	uncertain significance	Bardet-Biedl syndrome 8	2021-10-26	criteria provided, single submitter	clinical testing
Ambry Genetics	RCV002533215	SCV003688434	likely benign	Inborn genetic diseases	2021-12-17	criteria provided, single submitter	clinical testing	This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.
Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet	RCV000787890	SCV000926906	likely pathogenic	Macular dystrophy	2018-04-01	no assertion criteria provided	research
PreventionGenetics, part of Exact Sciences	RCV003928075	SCV004746366	likely benign	TTC8-related disorder	2022-07-05	no assertion criteria provided	clinical testing	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).