Genetic Variant TTLL3:c.-171C>T (chr3-9810265-C-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_001025930.5(TTLL3):c.259C>T(p.Pro87Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000398 in 1,507,362 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/18 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000037 ( 0 hom. )

Consequence

TTLL3
NM_001025930.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -0.116

Variant links:

Genes affected

TTLL3 (HGNC:24483): (tubulin tyrosine ligase like 3) Enables protein-glycine ligase activity. Predicted to be involved in axoneme assembly and flagellated sperm motility. Predicted to be located in axoneme; microtubule cytoskeleton; and sperm flagellum. [provided by Alliance of Genome Resources, Apr 2022]

TTLL3 links:

ARPC4-TTLL3 (HGNC:38830): (ARPC4-TTLL3 readthrough) This locus represents naturally occurring read-through transcription between the neighboring ARPC4 (actin related protein 2/3 complex, subunit 4) and TTLL3 (tubulin tyrosine ligase-like family, member 3) genes. The read-through transcript encodes a fusion protein that shares sequence identity with each individual gene product. [provided by RefSeq, Nov 2010]

ARPC4-TTLL3 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.053043783).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTLL3	NM_001387446.1 link	c.-171C>T		5_prime_UTR_variant	Exon 1 of 14	ENST00000685419.1	NP_001374375.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTLL3	ENST00000685419 link	c.-171C>T		5_prime_UTR_variant	Exon 1 of 14		NM_001387446.1	ENSP00000510679.1		A0A8I5KXU2
ARPC4-TTLL3	ENST00000397256.5 link	c.331-2678C>T		intron_variant	Intron 4 of 11	5		ENSP00000380427.1		A0A0A6YYG9

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152126

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000194

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000997

AC:

AN:

100288

Hom.:

AF XY:

0.00

AC XY:

AN XY:

56132

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000166

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000369

AC:

AN:

1355236

Hom.:

Cov.:

AF XY:

0.00000449

AC XY:

AN XY:

668468

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000621

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000281

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152126

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74304

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000194

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Mar 14, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.259C>T (p.P87S) alteration is located in exon 1 (coding exon 1) of the TTLL3 gene. This alteration results from a C to T substitution at nucleotide position 259, causing the proline (P) at amino acid position 87 to be replaced by a serine (S). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.45

BayesDel_noAF

Benign

-0.62

CADD

Benign

9.1

DANN

Benign

0.93

Eigen

Benign

-0.67

Eigen_PC

Benign

-0.80

FATHMM_MKL

Benign

0.057

LIST_S2

Benign

0.38

M_CAP

Benign

0.035

MetaRNN

Benign

0.053

MetaSVM

Benign

-0.91

PrimateAI

Uncertain

0.60

PROVEAN

Benign

-1.4

REVEL

Benign

0.032

Sift

Benign

0.46

Sift4G

Benign

0.49

Vest4

0.046

MutPred

0.15

Loss of glycosylation at P89 (P = 0.0196);

MVP

0.15

MPC

0.093

ClinPred

0.042

GERP RS

2.4

gMVP

0.053

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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