NM_020458.4:c.280A>T

Variant names:

• chr2-46950458-A-T
• rs766411601
• NM_020458.4:c.280A>T

Variant summary

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

The NM_020458.4(TTC7A):​c.280A>T​(p.Lys94*) variant causes a stop gained change. The variant was absent in control chromosomes in GnomAD project. 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)
• Consequence: TTC7A NM_020458.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.24
• Publications: 1 publications found

Genes affected

TTC7A (HGNC:19750): (tetratricopeptide repeat domain 7A) This gene encodes a protein containing tetratricopeptide repeats. Mutations in this gene disrupt intestinal development and can cause early onset inflammatory bowel disease and intestinal atresia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jun 2014]

TTC7A Gene-Disease associations (from GenCC):

• gastrointestinal defects and immunodeficiency syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• multiple intestinal atresia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Ambry Genetics

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 2-46950458-A-T is Pathogenic according to our data. Variant chr2-46950458-A-T is described in ClinVar as Pathogenic. ClinVar VariationId is 640974.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC7A	NM_020458.4	c.280A>T	p.Lys94*	stop_gained	Exon 2 of 20	ENST00000319190.11	NP_065191.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTC7A	ENST00000319190.11	c.280A>T	p.Lys94*	stop_gained	Exon 2 of 20	2	NM_020458.4	ENSP00000316699.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Multiple gastrointestinal atresias Pathogenic:1

Nov 05, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in TTC7A are known to be pathogenic (PMID: 23830146, 24292712). This variant has not been reported in the literature in individuals with TTC7A-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Lys94*) in the TTC7A gene. It is expected to result in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	39
DANN	Uncertain	0.99
Eigen	Pathogenic	0.70
Eigen_PC	Uncertain	0.56
FATHMM_MKL	Uncertain	0.96	D
PhyloP100		5.2
Vest4		0.42
GERP RS		4.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Mutation Taster		=2/198	disease causing (ClinVar)

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: rs766411601; hg19: chr2-47177597;