Genetic Variant RTTN:c.6153+5G>A (chr18-70020610-C-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_173630.4(RTTN):c.6153+5G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000391 in 1,610,190 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 (★★).

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

RTTN
NM_173630.4 splice_region, intron

Scores

Splicing: ADA: 0.9964

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 2.96

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:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RTTN	NM_173630.4 link	c.6153+5G>A		splice_region_variant, intron_variant	Intron 45 of 48	ENST00000640769.2	NP_775901.3	Q86VV8-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RTTN	ENST00000640769.2 link	c.6153+5G>A		splice_region_variant, intron_variant	Intron 45 of 48	2	NM_173630.4	ENSP00000491507.1		Q86VV8-1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152162

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.000288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000644

AC:

AN:

248262

Hom.:

AF XY:

0.0000668

AC XY:

AN XY:

134686

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000977

Gnomad OTH exome

AF:

0.000166

GnomAD4 exome

AF:

0.0000391

AC:

AN:

1458028

Hom.:

Cov.:

AF XY:

0.0000359

AC XY:

AN XY:

725222

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000112

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.0000750

Gnomad4 NFE exome

AF:

0.0000325

Gnomad4 OTH exome

AF:

0.000133

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152162

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74320

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.000288

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000774

Hom.:

Bravo

AF:

0.0000453

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Oct 22, 2013

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 45 of the RTTN gene. It does not directly change the encoded amino acid sequence of the RTTN protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs587780443, gnomAD 0.01%). 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: 130192). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus 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. -

Microcephalic primordial dwarfism due to RTTN deficiency

Uncertain:1

Sep 17, 2021

Pittsburgh Clinical Genomics Laboratory, University of Pittsburgh Medical Center

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change is a single nucleotide substitution 5 base pairs downstream of exon 45 of RTTN. This is a previously reported variant (ClinVar) that has not been reported in patients in the literature with RTTN-related disease. This variant is rare in control population datasets (gnomAD database 17/279660 alleles or 0.006%). Multiple bioinformatic tools predict that this variant would affect gene splicing, and the G nucleotide at this position is highly conserved across the vertebrate species examined. Functiol studies confirming an effect on splicing have not been performed, to our knowledge. At this time, there is insufficient evidence to determine if this variant is pathogenic or benign. Therefore, we consider this a variant of uncertain significance. ACMG Criteria: PM2 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.40

CADD

Benign

DANN

Benign

0.61

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Benign

0.60

SpliceAI score (max)

0.32

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.32

Position offset: 5

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