chr12-123706829-C-T

Variant names:

• chr12-123706829-C-T
• rs863225426
• NM_024809.5:c.1873C>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_024809.5(TCTN2):​c.1873C>T​(p.Gln625*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TCTN2 NM_024809.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 2.15
• Publications: 1 publications found

Genes affected

TCTN2 (HGNC:25774): (tectonic family member 2) This gene encodes a type I membrane protein that belongs to the tectonic family. Studies in mice suggest that this protein may be involved in hedgehog signaling, and essential for ciliogenesis. Mutations in this gene are associated with Meckel syndrome type 8. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2011]

TCTN2 Gene-Disease associations (from GenCC):

• Joubert syndrome 24

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: ClinGen, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• Joubert syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• Meckel syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-123706829-C-T is Pathogenic according to our data. Variant chr12-123706829-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 218100.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_024809.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TCTN2	NM_024809.5	MANE Select	c.1873C>T	p.Gln625*	stop_gained	Exon 16 of 18	NP_079085.2
	TCTN2	NM_001143850.3		c.1870C>T	p.Gln624*	stop_gained	Exon 16 of 18	NP_001137322.1
	TCTN2	NM_001410989.1		c.1738C>T	p.Gln580*	stop_gained	Exon 15 of 17	NP_001397918.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TCTN2	ENST00000303372.7	TSL:1 MANE Select	c.1873C>T	p.Gln625*	stop_gained	Exon 16 of 18	ENSP00000304941.5
	TCTN2	ENST00000426174.6	TSL:2	c.1870C>T	p.Gln624*	stop_gained	Exon 16 of 18	ENSP00000395171.2
	TCTN2	ENST00000965363.1		c.1795C>T	p.Gln599*	stop_gained	Exon 15 of 17	ENSP00000635422.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461892 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 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: 0.0000252 AC: 1 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112012

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

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Joubert syndrome 24 (1)
1	-	-	Meckel-Gruber syndrome;C0431399:Joubert syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	36
DANN	Benign	0.97
Eigen	Uncertain	0.34
Eigen_PC	Benign	0.023
FATHMM_MKL	Benign	0.24	N
PhyloP100		2.1
Vest4		0.30
GERP RS		3.3
Mutation Taster		=3/197	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs863225426; hg19: chr12-124191376;