rs772137594

Positions:

• chr18-70190651-A-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_173630.4(RTTN):​c.1076T>C​(p.Ile359Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,342 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict 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. I359V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: RTTN NM_173630.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.790

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]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.031578213).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RTTN	NM_173630.4	c.1076T>C	p.Ile359Thr	missense_variant	9/49	ENST00000640769.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RTTN	ENST00000640769.2	c.1076T>C	p.Ile359Thr	missense_variant	9/49	2	NM_173630.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000120 AC: 3 AN: 249492 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 135346

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000177

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461342 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 727028

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000827 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Nov 19, 2015

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 27, 2022

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 359 of the RTTN protein (p.Ile359Thr). This variant is present in population databases (rs772137594, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with RTTN-related conditions. ClinVar contains an entry for this variant (Variation ID: 436603). 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 threonine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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	0.062
BayesDel_addAF	Benign	-0.31	T
BayesDel_noAF	Benign	-0.59
CADD	Benign	13
DANN	Benign	0.87
DEOGEN2	Benign	0.043	T;.;.
Eigen	Benign	-0.87
Eigen_PC	Benign	-0.77
FATHMM_MKL	Benign	0.13	N
LIST_S2	Benign	0.72	T;T;T
M_CAP	Benign	0.011	T
MetaRNN	Benign	0.032	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.1	L;L;.
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.26	T
PROVEAN	Benign	-0.12	.;N;.
REVEL	Benign	0.082
Sift	Benign	0.49	.;T;.
Sift4G	Benign	0.37	.;T;.
Polyphen		0.0010	B;.;.
Vest4		0.055
MutPred		0.28		Gain of relative solvent accessibility (P = 0.0082);Gain of relative solvent accessibility (P = 0.0082);.;
MVP		0.17
MPC		0.089
ClinPred		0.045	T
GERP RS		2.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.077
gMVP		0.096

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

Publications

LitVar

Other links and lift over

dbSNP: rs772137594; hg19: chr18-67857887;