2-165941103-G-A

Position:

• chr2-165941103-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_024753.5(TTC21B):​c.634C>T​(p.Leu212Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,642 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TTC21B NM_024753.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.947

Genes affected

TTC21B (HGNC:25660): (tetratricopeptide repeat domain 21B) This gene encodes a member of TTC21 family, containing several tetratricopeptide repeat (TPR) domains. This protein is localized to the cilium axoneme, and may play a role in retrograde intraflagellar transport in cilia. Mutations in this gene are associated with various ciliopathies, nephronophthisis 12, and asphyxiating thoracic dystrophy 4. [provided by RefSeq, Oct 2011]

TTC21B-AS1 (HGNC:41115): (TTC21B antisense RNA 1)

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTC21B	NM_024753.5	c.634C>T	p.Leu212Phe	missense_variant	6/29	ENST00000243344.8	NP_079029.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTC21B	ENST00000243344.8	c.634C>T	p.Leu212Phe	missense_variant	6/29	1	NM_024753.5	ENSP00000243344.7

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461642 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727122

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Asphyxiating thoracic dystrophy 4;C3151186:Nephronophthisis 12 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

May 17, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.43
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Benign	0.39	T
Eigen	Uncertain	0.21
Eigen_PC	Benign	0.17
FATHMM_MKL	Benign	0.72	D
LIST_S2	Benign	0.68	T
M_CAP	Benign	0.018	T
MetaRNN	Uncertain	0.46	T
MetaSVM	Benign	-0.73	T
MutationAssessor	Uncertain	2.4	M
PrimateAI	Benign	0.46	T
PROVEAN	Uncertain	-2.9	D
REVEL	Benign	0.23
Sift	Benign	0.030	D
Sift4G	Uncertain	0.028	D
Polyphen		0.97	D
Vest4		0.39
MutPred		0.76		Gain of helix (P = 0.132);
MVP		0.54
MPC		0.092
ClinPred		0.95	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.12
gMVP		0.34

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

Other links and lift over

dbSNP: rs1687351462; hg19: chr2-166797613;