3-39110988-A-C

Variant names:

• chr3-39110988-A-C
• rs754402212
• NM_001366900.1:c.406A>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001366900.1(TTC21A):​c.406A>C​(p.Met136Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M136V) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TTC21A NM_001366900.1 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.86
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.17863011).

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC21A	NM_001366900.1	MANE Select	c.406A>C	p.Met136Leu	missense	Exon 4 of 29	NP_001353829.1	A0A804HK20
	TTC21A	NM_001366899.1		c.406A>C	p.Met136Leu	missense	Exon 4 of 29	NP_001353828.1	A0A140VJY5
	TTC21A	NM_145755.3		c.406A>C	p.Met136Leu	missense	Exon 4 of 29	NP_665698.2	Q8NDW8-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC21A	ENST00000683103.1	MANE Select	c.406A>C	p.Met136Leu	missense	Exon 4 of 29	ENSP00000507739.1	A0A804HK20
	TTC21A	ENST00000431162.6	TSL:1	c.406A>C	p.Met136Leu	missense	Exon 4 of 29	ENSP00000398211.2	Q8NDW8-1
	TTC21A	ENST00000479954.5	TSL:1	n.527A>C		non_coding_transcript_exon	Exon 4 of 7

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Benign	-0.068	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	12
DANN	Benign	0.54
DEOGEN2	Benign	0.013	T
Eigen	Benign	-0.68
Eigen_PC	Benign	-0.62
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Benign	0.78	T
M_CAP	Benign	0.0077	T
MetaRNN	Benign	0.18	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.8	L
PhyloP100		2.9
PrimateAI	Benign	0.30	T
PROVEAN	Benign	-2.1	N
REVEL	Benign	0.10
Sift	Benign	0.11	T
Sift4G	Benign	0.065	T
Polyphen		0.0	B
Vest4		0.27
MutPred		0.47		Loss of glycosylation at K138 (P = 0.0553)
MVP		0.66
MPC		0.12
ClinPred		0.11	T
GERP RS		2.0
Varity_R		0.16
gMVP		0.18
Mutation Taster		=91/9	polymorphism

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

Other links and lift over

dbSNP: rs754402212; hg19: chr3-39152479;