chr10-95664119-A-G

Variant names:

• chr10-95664119-A-G
• rs2097923898
• NM_015631.6:c.1772T>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_015631.6(TCTN3):​c.1772T>C​(p.Ile591Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000547 in 1,461,884 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I591F) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: TCTN3 NM_015631.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.312
• Publications: 0 publications found

Genes affected

TCTN3 (HGNC:24519): (tectonic family member 3) This gene encodes a member of the tectonic gene family which functions in Hedgehog signal transduction and development of the neural tube. Mutations in this gene have been associated with Orofaciodigital Syndrome IV and Joubert Syndrom 18. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Sep 2012]

TCTN3 Gene-Disease associations (from GenCC):

• ciliopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• orofaciodigital syndrome IV

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Orphanet, Laboratory for Molecular Medicine
• Joubert syndrome 18

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• Meckel syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• orofaciodigital syndrome type 6

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.115876496).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCTN3	NM_015631.6	c.1772T>C	p.Ile591Thr	missense_variant	Exon 14 of 14	ENST00000371217.10	NP_056446.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TCTN3	ENST00000371217.10	c.1772T>C	p.Ile591Thr	missense_variant	Exon 14 of 14	1	NM_015631.6	ENSP00000360261.5
TCTN3	ENST00000265993.13	c.1826T>C	p.Ile609Thr	missense_variant	Exon 14 of 14	1		ENSP00000265993.9
TCTN3	ENST00000430368.6	c.1328T>C	p.Ile443Thr	missense_variant	Exon 10 of 10	2		ENSP00000387567.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461884 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727246

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.000126 AC: 5 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1112006

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Orofacial-digital syndrome IV;C3553758:Joubert syndrome 18 Uncertain:1

Aug 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. This variant has not been reported in the literature in individuals affected with TCTN3-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 591 of the TCTN3 protein (p.Ile591Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.16	T
BayesDel_noAF	Benign	-0.47
CADD	Benign	6.6
DANN	Benign	0.94
DEOGEN2	Benign	0.0063	T;T;.;.
Eigen	Benign	-0.86
Eigen_PC	Benign	-0.85
FATHMM_MKL	Benign	0.13	N
LIST_S2	Benign	0.49	T;.;T;T
M_CAP	Benign	0.014	T
MetaRNN	Benign	0.12	T;T;T;T
MetaSVM	Benign	-0.78	T
MutationAssessor	Benign	1.5	L;L;.;.
PhyloP100		0.31
PrimateAI	Benign	0.27	T
PROVEAN	Benign	-0.52	.;.;.;N
REVEL	Benign	0.19
Sift	Uncertain	0.017	.;.;.;D
Sift4G	Uncertain	0.040	D;D;D;D
Polyphen		0.0010	B;B;.;.
Vest4		0.10
MutPred		0.46		Loss of stability (P = 0.078);Loss of stability (P = 0.078);.;.;
MVP		0.23
MPC		0.18
ClinPred		0.037	T
GERP RS		2.3
Varity_R		0.036
gMVP		0.46
Mutation Taster		=86/14	polymorphism

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

Other links and lift over

dbSNP: rs2097923898; hg19: chr10-97423876;