Genetic Variant TTC21A:p.Ala129Thr (chr3-39110967-G-A) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_001366900.1(TTC21A):c.385G>A(p.Ala129Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,613,776 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 Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

TTC21A
NM_001366900.1 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 9.55

Publications

0 publications found

Variant links:

Genes affected

TTC21A (HGNC:30761): (tetratricopeptide repeat domain 21A) Involved in flagellated sperm motility and spermatid development. Predicted to be located in cilium. Predicted to be part of intraciliary transport particle A. Implicated in spermatogenic failure 37. [provided by Alliance of Genome Resources, Apr 2022]

TTC21A Gene-Disease associations (from GenCC):

spermatogenic failure 37
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
non-syndromic male infertility due to sperm motility disorder
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

TTC21A links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.914

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001366900.1. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TTC21A	NM_001366900.1	MANE Select	c.385G>A	p.Ala129Thr	missense	Exon 4 of 29	NP_001353829.1	A0A804HK20
TTC21A	NM_001366899.1		c.385G>A	p.Ala129Thr	missense	Exon 4 of 29	NP_001353828.1	A0A140VJY5
TTC21A	NM_145755.3		c.385G>A	p.Ala129Thr	missense	Exon 4 of 29	NP_665698.2	Q8NDW8-1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TTC21A	ENST00000683103.1	MANE Select	c.385G>A	p.Ala129Thr	missense	Exon 4 of 29	ENSP00000507739.1	A0A804HK20
TTC21A	ENST00000431162.6	TSL:1	c.385G>A	p.Ala129Thr	missense	Exon 4 of 29	ENSP00000398211.2	Q8NDW8-1
TTC21A	ENST00000479954.5	TSL:1	n.506G>A		non_coding_transcript_exon	Exon 4 of 7

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152216

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000120

AC:

AN:

249158

AF XY:

0.00000739

show subpopulations

Gnomad AFR exome

AF:

0.000194

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS 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:

0.00000205

AC:

AN:

1461560

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727042

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000598

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53270

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111882

Other (OTH)

AF:

0.0000166

AC:

AN:

60376

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000343967), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.392

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152216

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74372

show subpopulations

African (AFR)

AF:

0.0000724

AC:

AN:

41458

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5206

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000264

ESP6500AA

AF:

0.000253

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000248

AC:

ClinVar

ClinVar submissions

Significance:Uncertain significance

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.37

BayesDel_addAF

Pathogenic

0.22

BayesDel_noAF

Pathogenic

0.36

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.26

Eigen

Pathogenic

0.91

Eigen_PC

Pathogenic

0.85

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

0.99

M_CAP

Benign

0.075

MetaRNN

Pathogenic

0.91

MetaSVM

Pathogenic

0.81

MutationAssessor

Pathogenic

3.3

PhyloP100

9.6

PrimateAI

Benign

0.45

PROVEAN

Uncertain

-3.8

REVEL

Pathogenic

0.85

Sift

Uncertain

0.0020

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.85

MVP

0.97

MPC

0.58

ClinPred

0.98

GERP RS

5.7

Varity_R

0.62

gMVP

0.42

Mutation Taster

=51/49

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over