chr18-70004174-C-G

Position:

chr18-70004174-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 4P and 3B. PM2PM5BP4_ModerateBS1_Supporting

The NM_173630.4(RTTN):c.6658G>C(p.Val2220Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000278 in 1,613,394 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V2220M) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00030 ( 0 hom. )

Consequence

RTTN
NM_173630.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 1.13

Variant links:

Genes affected

RTTN (HGNC:18654): (rotatin) This gene encodes a large protein whose specific function is unknown. Absence of the orthologous protein in mouse results in embryonic lethality with deficient axial rotation, abnormal differentiation of the neural tube, and randomized looping of the heart tube during development. In human, mutations in this gene are associated with polymicrogyria with seizures. In human fibroblasts this protein localizes at the ciliary basal bodies. Given the intracellular localization of this protein and the phenotypic effects of mutations, this gene is suspected of playing a role in the maintenance of normal ciliary structure which in turn effects the developmental process of left-right organ specification, axial rotation, and perhaps notochord development. [provided by RefSeq, Jan 2013]

RTTN links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr18-70004174-C-T is described in Lovd as [Likely_pathogenic].

BP4

Computational evidence support a benign effect (MetaRNN=0.09453559).

BS1

Variant frequency is greater than expected in population nfe. gnomad4_exome allele frequency = 0.000296 (432/1461230) while in subpopulation NFE AF= 0.000375 (417/1111474). AF 95% confidence interval is 0.000345. There are 0 homozygotes in gnomad4_exome. There are 217 alleles in male gnomad4_exome subpopulation. Median coverage is 29. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
RTTN	NM_173630.4 linkuse as main transcript	c.6658G>C	p.Val2220Leu	missense_variant	49/49	ENST00000640769.2	NP_775901.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
RTTN	ENST00000640769.2 linkuse as main transcript	c.6658G>C	p.Val2220Leu	missense_variant	49/49	2	NM_173630.4	ENSP00000491507	P1	Q86VV8-1

Frequencies

GnomAD3 genomes

AF:

0.000112

AC:

AN:

152046

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000656

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000385

Gnomad SAS

AF:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000842

AC:

AN:

249288

Hom.:

AF XY:

0.0000961

AC XY:

AN XY:

135232

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000167

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000141

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000296

AC:

432

AN:

1461230

Hom.:

Cov.:

AF XY:

0.000299

AC XY:

217

AN XY:

726964

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000580

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000375

Gnomad4 OTH exome

AF:

0.0000994

GnomAD4 genome

AF:

0.000112

AC:

AN:

152164

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74386

show subpopulations

Gnomad4 AFR

AF:

0.0000482

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000386

Gnomad4 SAS

AF:

0.000415

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000336

Hom.:

Bravo

AF:

0.0000945

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000778

AC:

ExAC

AF:

0.0000745

AC:

EpiCase

AF:

0.000218

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 21, 2022

The c.6658G>C (p.V2220L) alteration is located in exon 49 (coding exon 49) of the RTTN gene. This alteration results from a G to C substitution at nucleotide position 6658, causing the valine (V) at amino acid position 2220 to be replaced by a leucine (L). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 05, 2022

This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 2220 of the RTTN protein (p.Val2220Leu). This variant is present in population databases (rs201561378, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with RTTN-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The leucine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.29

BayesDel_noAF

Benign

-0.39

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Benign

0.029

T;.

Eigen

Benign

-0.14

Eigen_PC

Benign

-0.13

FATHMM_MKL

Benign

0.65

LIST_S2

Benign

0.70

T;T

M_CAP

Benign

0.013

MetaRNN

Benign

0.095

T;T

MetaSVM

Benign

-1.1

MutationAssessor

Uncertain

2.2

M;.

MutationTaster

Benign

1.0

D;N

PrimateAI

Benign

0.35

Polyphen

0.83

P;.

MutPred

0.32

Gain of disorder (P = 0.0426);.;

ClinPred

0.028

GERP RS

4.2

Varity_R

0.053

gMVP

0.13

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.20

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.20

Position offset: -6

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over