rs151317740

Positions:

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2BP4_ModerateBS1_Supporting

The NM_020458.4(TTC7A):c.1026C>G(p.Ile342Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00068 in 1,614,052 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/21 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. I342F) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00038 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00071 ( 1 hom. )

Consequence

TTC7A
NM_020458.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: -2.09

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.09153226).

BS1

Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.000381 (58/152190) while in subpopulation NFE AF= 0.000632 (43/68020). AF 95% confidence interval is 0.000482. There are 0 homozygotes in gnomad4. There are 34 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTC7A	NM_020458.4 linkuse as main transcript	c.1026C>G	p.Ile342Met	missense_variant	8/20	ENST00000319190.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTC7A	ENST00000319190.11 linkuse as main transcript	c.1026C>G	p.Ile342Met	missense_variant	8/20	2	NM_020458.4	P1	Q9ULT0-1

Frequencies

GnomAD3 genomes

AF:

0.000381

AC:

AN:

152190

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000193

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000327

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:

0.000632

Gnomad OTH

AF:

0.000956

GnomAD3 exomes

AF:

0.000298

AC:

AN:

251384

Hom.:

AF XY:

0.000309

AC XY:

AN XY:

135882

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.000492

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:

0.000449

Gnomad OTH exome

AF:

0.000815

GnomAD4 exome

AF:

0.000711

AC:

1040

AN:

1461862

Hom.:

Cov.:

AF XY:

0.000661

AC XY:

481

AN XY:

727236

show subpopulations

Gnomad4 AFR exome

AF:

0.0000896

Gnomad4 AMR exome

AF:

0.000559

Gnomad4 ASJ exome

AF:

0.0000383

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.0000749

Gnomad4 NFE exome

AF:

0.000858

Gnomad4 OTH exome

AF:

0.000878

GnomAD4 genome

AF:

0.000381

AC:

AN:

152190

Hom.:

Cov.:

AF XY:

0.000457

AC XY:

AN XY:

74350

show subpopulations

Gnomad4 AFR

AF:

0.000193

Gnomad4 AMR

AF:

0.000327

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000632

Gnomad4 OTH

AF:

0.000956

Alfa

AF:

0.000108

Hom.:

Bravo

AF:

0.000480

TwinsUK

AF:

0.00216

AC:

ALSPAC

AF:

0.000778

AC:

ExAC

AF:

0.000288

AC:

EpiCase

AF:

0.000491

EpiControl

AF:

0.000474

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 31, 2024

The c.1026C>G (p.I342M) alteration is located in exon 8 (coding exon 8) of the TTC7A gene. This alteration results from a C to G substitution at nucleotide position 1026, causing the isoleucine (I) at amino acid position 342 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Multiple gastrointestinal atresias

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 23, 2022

This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 342 of the TTC7A protein (p.Ile342Met). This variant is present in population databases (rs151317740, gnomAD 0.06%). This variant has not been reported in the literature in individuals affected with TTC7A-related conditions. ClinVar contains an entry for this variant (Variation ID: 528462). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.38

BayesDel_noAF

Benign

-0.44

CADD

Benign

7.9

DANN

Uncertain

0.99

DEOGEN2

Benign

0.054

.;T;.

Eigen

Benign

-0.65

Eigen_PC

Benign

-0.81

FATHMM_MKL

Benign

0.040

LIST_S2

Uncertain

0.92

D;D;D

M_CAP

Benign

0.015

MetaRNN

Benign

0.092

T;T;T

MetaSVM

Benign

-0.91

MutationAssessor

Benign

1.7

.;L;L

MutationTaster

Benign

1.0

D;N;N;N

PrimateAI

Uncertain

0.60

PROVEAN

Benign

-0.65

N;N;N

REVEL

Benign

0.12

Sift

Benign

0.15

T;D;D

Sift4G

Benign

0.075

T;T;T

Polyphen

0.95

P;P;.

Vest4

0.52

MVP

0.20

MPC

0.23

ClinPred

0.087

GERP RS

-7.1

Varity_R

0.050

gMVP

0.25

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