rs759086770

Variant names:

• chr2-165883873-A-G
• rs759086770
• NM_024753.5:c.3605T>C

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PP3_Strong PP5

The NM_024753.5(TTC21B):​c.3605T>C​(p.Leu1202Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000821 in 1,461,828 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 Likely pathogenic (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: TTC21B NM_024753.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic no assertion criteria provided P:3
• Conservation: PhyloP100: 9.32
• Publications: 1 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 Gene-Disease associations (from GenCC):

• nephronophthisis 12

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae)
• asphyxiating thoracic dystrophy 4

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• Jeune syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• nephronophthisis 2

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.945
• PP5: Variant 2-165883873-A-G is Pathogenic according to our data. Variant chr2-165883873-A-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 446651.Status of the report is no_assertion_criteria_provided, 0 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_024753.5. 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
	TTC21B	NM_024753.5	MANE Select	c.3605T>C	p.Leu1202Pro	missense	Exon 26 of 29	NP_079029.3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC21B	ENST00000243344.8	TSL:1 MANE Select	c.3605T>C	p.Leu1202Pro	missense	Exon 26 of 29	ENSP00000243344.7
	TTC21B	ENST00000679840.1		c.3605T>C	p.Leu1202Pro	missense	Exon 26 of 27	ENSP00000505248.1
	TTC21B	ENST00000679799.1		c.3605T>C	p.Leu1202Pro	missense	Exon 26 of 28	ENSP00000505208.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461828 Hom.: 0 Cov.: 32 AF XY: 0.00000688 AC XY: 5 AN XY: 727218

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.0000108 AC: 12 AN: 1111974

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000354 Hom.: 0

Bravo AF: 0.00000756

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic/Likely pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
2	-	-	Type IV short rib polydactyly syndrome (2)
1	-	-	Asphyxiating thoracic dystrophy 4 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.81	T
M_CAP	Benign	0.085	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Uncertain	-0.045	T
MutationAssessor	Pathogenic	3.5	M
PhyloP100		9.3
PrimateAI	Uncertain	0.61	T
PROVEAN	Pathogenic	-5.9	D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.99
MVP		0.51
MPC		0.28
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.98
gMVP		0.88
Mutation Taster		=7/93	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs759086770; hg19: chr2-166740383;