2-165941046-T-C

Variant names:

• chr2-165941046-T-C
• rs149925563
• NM_024753.5:c.691A>G

Variant summary

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

The NM_024753.5(TTC21B):​c.691A>G​(p.Thr231Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,632 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T231S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TTC21B NM_024753.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.70
• Publications: 0 publications found

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

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=0.1356265).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC21B	NM_024753.5	c.691A>G	p.Thr231Ala	missense_variant	Exon 6 of 29	ENST00000243344.8	NP_079029.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTC21B	ENST00000243344.8	c.691A>G	p.Thr231Ala	missense_variant	Exon 6 of 29	1	NM_024753.5	ENSP00000243344.7

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461632 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727114

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.00 AC: 0 AN: 44700

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.00 AC: 0 AN: 39686

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111830

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.073
BayesDel_addAF	Benign	-0.18	T
BayesDel_noAF	Benign	-0.50
CADD	Benign	13
DANN	Benign	0.95
DEOGEN2	Benign	0.21	T
Eigen	Benign	-0.43
Eigen_PC	Benign	-0.26
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.82	T
M_CAP	Benign	0.0069	T
MetaRNN	Benign	0.14	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.1	L
PhyloP100		1.7
PrimateAI	Benign	0.31	T
PROVEAN	Benign	-2.3	N
REVEL	Benign	0.054
Sift	Benign	0.34	T
Sift4G	Benign	0.54	T
Vest4		0.19
ClinPred		0.24	T
GERP RS		4.0
Varity_R		0.062
gMVP		0.34
Mutation Taster		=83/17	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs149925563; hg19: chr2-166797556;