Study of the Pathophysiology of RNU4ATAC and RTTN Associated Syndromes

NCT ID: NCT06111950

Last Updated: 2024-10-09

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

45 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-08-27

Study Completion Date

2029-08-27

Brief Summary

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In the human genome, about 750 genes contain one intron excised by the minor spliceosome. These genes are named U12 genes, and these introns, minor or U12 introns. The minor spliceosome comprises its own set of snRNAs, among which U4atac. Its non-coding gene, RNU4ATAC, has been found mutated in Taybi-Linder (TALS), Roifman (RFMN) and Lowry-Wood syndromes (LWS). These rare developmental disorders associate ante- and post-natal growth retardation, microcephaly, skeletal dysplasia, intellectual disability, retinal dystrophy and immunodeficiency. Their physiopathological mechanisms remain unsolved: the number of U12 genes involved, their identity and function, or the cellular mechanisms impacted by the splicing defect, are still unknown.

The hypothesis of the study is that U12 genes coding for primary cilia components are particularly sensitive to minor splicing defects caused by RNU4ATAC mutations. Indeed, a child showing signs of TALS but negative for RNU4ATAC was found to carry a homozygous variant in the RTTN gene, coding for the rotatin protein located at the centrosome and the base of the primary cilia and playing a role in maintaining these structures. In addition, bi-allelic RNU4ATAC mutations were identified in five patients presenting with traits suggestive of the Joubert syndrome (JBTS), a well-characterized ciliopathy. These patients also present with traits typical of TALS/RFMN/LWS.

To better understand the causes of these pathologies, a cohort of patients with syndromes associated with bi-allele mutations of the RNU4ATAC or RTTN gene will be gathered, in order to conduct studies on the cells of these patients. Blood samples will be taken, as well as skin biopsies, if possible. These samples will be used to create induced pluripotent stem cell lines. Blood samples will also be collected from the parents of RNU4ATAC patients, to eliminate in transcriptomic analyses expression variations due to differences in genetic background. Biopsies of skin, muscle and brain tissue will be collected on foetuses carrying two-allele RNU4ATAC or RTTN mutations whose parents have had a miscarriage or have chosen to have a medical abortion. The biological samples collected will be used to study the transcription level of U12 genes, the splicing of their pre-messenger RNA, their main cellular functions, and the structural characteristics of tissues and cells.

Detailed Description

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Conditions

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Taybi Linder Syndrome Microcephalic Osteodysplastic Primordial Dwarfism Types I and III Roifman Syndrome Lowry Wood Syndrome

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

SINGLE_GROUP

Primary Study Purpose

OTHER

Blinding Strategy

NONE

Study Groups

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RNU4ATAC patient

Patient with bi-allelic mutation of the RNU4ATAC gene

Group Type OTHER

Blood samples

Intervention Type OTHER

Blood samples of 5 ml to 15 ml depending on their weight

Skin biopsies

Intervention Type OTHER

Biopsies of fragment of skin 2 to 3 mm long by 1 mm wide and 1 mm deep will preferably be taken on the inside of the arm, in the upper third, between the bend of the elbow and the hollow of the armpit under strict sterility conditions.

RNU4ATAC fetus

Fetus with bi-allelic mutation of the RNU4ATAC gene

Group Type OTHER

Fetal samples

Intervention Type OTHER

Skin, muscle, brain and bone biopsies will be collected from fetuses in the autopsy room after the medical termination of pregnancy or miscarriage

RNU4ATAC parent

Parent of patient or fetus with bi-allelic mutation of the RNU4ATAC gene and who present themselve mono-allelic mutation of the RNU4ATAC gene

Group Type OTHER

Blood samples

Intervention Type OTHER

Blood samples of 5 ml to 15 ml depending on their weight

RTTN patient

Patient with bi-allelic mutation of the RTTN gene

Group Type OTHER

Blood samples

Intervention Type OTHER

Blood samples of 5 ml to 15 ml depending on their weight

Skin biopsies

Intervention Type OTHER

Biopsies of fragment of skin 2 to 3 mm long by 1 mm wide and 1 mm deep will preferably be taken on the inside of the arm, in the upper third, between the bend of the elbow and the hollow of the armpit under strict sterility conditions.

RTTN fetus

Fetus with bi-allelic mutation of the RTTN gene

Group Type OTHER

Fetal samples

Intervention Type OTHER

Skin, muscle, brain and bone biopsies will be collected from fetuses in the autopsy room after the medical termination of pregnancy or miscarriage

Interventions

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Blood samples

Blood samples of 5 ml to 15 ml depending on their weight

Intervention Type OTHER

Skin biopsies

Biopsies of fragment of skin 2 to 3 mm long by 1 mm wide and 1 mm deep will preferably be taken on the inside of the arm, in the upper third, between the bend of the elbow and the hollow of the armpit under strict sterility conditions.

Intervention Type OTHER

Fetal samples

Skin, muscle, brain and bone biopsies will be collected from fetuses in the autopsy room after the medical termination of pregnancy or miscarriage

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

TALS, RFMN, LWS or other pathology patients

* Woman or man
* All ages
* Presence of bi-allelic mutations of RNU4ATAC or RTTN
* Written consent of parents or legal guardian(s)
* Affiliation to a Social Security scheme

Healthy participants (Parent of the patient)

* Woman or man
* Major
* Presence of mono-allelic mutations of RNU4ATAC
* Written consent of the participant
* Affiliation to a Social Security scheme

Parents having recourse to a medical termination of pregnancy or having had a spontaneous miscarriage (for fetus samples)

* Woman or man
* Major
* Presence of bi-allelic mutations of RNU4ATAC or RTTN in the fetus
* Written parental consent
* Affiliation to a Social Security scheme

Exclusion Criteria

Subject participating in another research including an exclusion period still in progress.
Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Hospices Civils de Lyon

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Centre de référence des anomalies du développement et syndromes malformatifs du Sud-Ouest Occitanie Réunion, CHU de Bordeaux-GH Pellegrin

Bordeaux, , France

Site Status NOT_YET_RECRUITING

Centre de référence anomalies du développement de Lyon, Hôpital Femme Mère Enfant

Bron, , France

Site Status RECRUITING

Centre de référence des anomalies du développement et syndromes malformatifs de l'Est, CHU de DIJON

Dijon, , France

Site Status NOT_YET_RECRUITING

Centre de référence des anomalies du développement et syndromes malformatifs de l'inter région Nord-Ouest, Hôpital J de Flandre

Lille, , France

Site Status NOT_YET_RECRUITING

Unité Fonctionelle d'embryo-fœtopathologie, Hôpital Necker-Enfants Malades

Paris, , France

Site Status NOT_YET_RECRUITING

Centre de référence des anomalies du développement et syndromes malformatifs de l'Ouest, Hôpital Sud

Rennes, , France

Site Status NOT_YET_RECRUITING

Countries

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France

Central Contacts

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Sylvie MAZOYER, Dr

Role: CONTACT

04 81 10 65 33 ext. +33

Patrick EDERY, Pr

Role: CONTACT

04 72 12 96 98 ext. +33

Facility Contacts

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Didier LACOMBE, MD, PhD

Role: primary

05 56 79 56 48 ext. +33

Patrick EDERY, MD, PhD

Role: primary

04 72 12 96 98

Laurence OLIVIER-FAIVRE, MD, PhD

Role: primary

03 80 29 53 13 ext. +33

Sylvie MANOUVRIER-HANU, MD, PhD

Role: primary

03 20 44 49 11 ext. +33

Tania ATTIE-BITTACH, MD, PhD

Role: primary

01 44 49 51 44 ext. +33

Sylvie ODENT, MD, PhD

Role: primary

02 99 26 67 44 ext. +33

Other Identifiers

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69HCL20_0599

Identifier Type: -

Identifier Source: org_study_id

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