chr2-165911404-A-G

Variant names:

• chr2-165911404-A-G
• rs387907060
• NM_024753.5:c.2384T>C
• TTC21B p.Leu795Pro

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_024753.5(TTC21B):​c.2384T>C​(p.Leu795Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (no stars). Synonymous variant affecting the same amino acid position (i.e. L795L) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TTC21B NM_024753.5 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.22
• Publications: 7 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):

• asphyxiating thoracic dystrophy 4

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• nephronophthisis 12

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

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

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.941
• PP5: Variant 2-165911404-A-G is Pathogenic according to our data. Variant chr2-165911404-A-G is described in ClinVar as Pathogenic. ClinVar VariationId is 30939.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.2384T>C	p.Leu795Pro	missense	Exon 18 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.2384T>C	p.Leu795Pro	missense	Exon 18 of 29	ENSP00000243344.7	Q7Z4L5-1
	TTC21B	ENST00000679840.1		c.2384T>C	p.Leu795Pro	missense	Exon 18 of 27	ENSP00000505248.1	A0A7P0T8P4
	TTC21B	ENST00000679799.1		c.2384T>C	p.Leu795Pro	missense	Exon 18 of 28	ENSP00000505208.1	A0A494C0N4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Asphyxiating thoracic dystrophy 4 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.90	D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		9.2
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-5.9	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Varity_R		0.99
gMVP		0.88
Mutation Taster		=5/95	disease causing (ClinVar)

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs387907060;

hg19: chr2-166767914;