2-165949632-G-C

Position:

• chr2-165949632-G-C

Variant summary

Our verdict is Benign. Variant got -19 ACMG points: 0P and 19B. BP4_Moderate BP6_Very_Strong BP7 BS1 BS2

The NM_024753.5(TTC21B):​c.114C>G​(p.Val38Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00153 in 1,613,594 control chromosomes in the GnomAD database, including 37 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0083 (22 hom., cov: 32)
  • Exomes 𝑓: 0.00082 (15 hom.)
• Consequence: TTC21B NM_024753.5 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:9
• Conservation: PhyloP100: 2.49

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 (HGNC:):

ACMG classification

Verdict is Benign. Variant got -19 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.39).
• BP6: Variant 2-165949632-G-C is Benign according to our data. Variant chr2-165949632-G-C is described in ClinVar as [Likely_benign]. Clinvar id is 130648.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=2.49 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00831 (1265/152232) while in subpopulation AFR AF= 0.0293 (1219/41536). AF 95% confidence interval is 0.028. There are 22 homozygotes in gnomad4. There are 568 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 22 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTC21B	NM_024753.5	c.114C>G	p.Val38Val	synonymous_variant	2/29	ENST00000243344.8	NP_079029.3
TTC21B	XM_017004967.2	c.114C>G	p.Val38Val	synonymous_variant	2/28		XP_016860456.1
TTC21B	XM_006712761.2	c.114C>G	p.Val38Val	synonymous_variant	2/23		XP_006712824.1
TTC21B	XM_011511872.3	c.114C>G	p.Val38Val	synonymous_variant	2/21		XP_011510174.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTC21B	ENST00000243344.8	c.114C>G	p.Val38Val	synonymous_variant	2/29	1	NM_024753.5	ENSP00000243344.7

Frequencies

GnomAD3 genomes AF: 0.00830 AC: 1263 AN: 152114 Hom.: 22 Cov.: 32

Gnomad AFR AF: 0.0294

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00255

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00239

GnomAD3 exomes AF: 0.00196 AC: 490 AN: 249670 Hom.: 7 AF XY: 0.00155 AC XY: 209 AN XY: 135118

Gnomad AFR exome AF: 0.0283

Gnomad AMR exome AF: 0.000811

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000654

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000492

GnomAD4 exome AF: 0.000820 AC: 1199 AN: 1461362 Hom.: 15 Cov.: 31 AF XY: 0.000710 AC XY: 516 AN XY: 726974

Gnomad4 AFR exome AF: 0.0310

Gnomad4 AMR exome AF: 0.000961

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000812

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000899

Gnomad4 OTH exome AF: 0.00161

GnomAD4 genome AF: 0.00831 AC: 1265 AN: 152232 Hom.: 22 Cov.: 32 AF XY: 0.00763 AC XY: 568 AN XY: 74432

Gnomad4 AFR AF: 0.0293

Gnomad4 AMR AF: 0.00255

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00237

Alfa AF: 0.000448 Hom.: 0

Bravo AF: 0.00966

Asia WGS AF: 0.000289 AC: 1 AN: 3476

EpiCase AF: 0.000164

EpiControl AF: 0.00

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:3

Likely benign, no assertion criteria provided	clinical testing	Genetic Services Laboratory, University of Chicago	-	Likely benign based on allele frequency in 1000 Genomes Project or ESP global frequency and its presence in a patient with a rare or unrelated disease phenotype. NOT Sanger confirmed. -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Oct 06, 2016	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -

not provided Benign:2

Benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -
Benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Oct 16, 2023	- -

Jeune thoracic dystrophy;C0687120:Nephronophthisis Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 30, 2024

- -

Asphyxiating thoracic dystrophy 4 Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Nephronophthisis 12 Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Connective tissue disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Genome Diagnostics Laboratory, The Hospital for Sick Children

May 01, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.39
CADD	Benign	15
DANN	Benign	0.77
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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

Publications

LitVar

Other links and lift over

dbSNP: rs34486024; hg19: chr2-166806142;