Clinical trial NCT05867979: Search for Structural Variants in Patients With DSD and Inconclusive Molecular Diagnosis
Official title: Search for Structural Variants in Patients With Disorders of Sex Development (DSD) and Inconclusive Molecular Diagnosis GENEXPLOR-DSD
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Disorder of Sex Development, 46,XY
Lead sponsor: University Hospital, Montpellier
Sponsor class: OTHER
First posted: 2023-05-22
Enrollment: 20
Sex: MALE
Minimum age (years): 6
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: This is a single-center molecular biology pilot study on a single group of 20 patients with a disorder of sex development and inconclusive molecular diagnosis.

The 20 blood samples from patients with severe or moderate DSD, with an inconclusive diagnosis will benefit from the Optical Genome Mapping.
Primary purpose: DIAGNOSTIC

Brief summary: The goal of this clinical trial is to identify structural variants by Optical Genome Mapping (OGM) in the described participant population.

The main questions it aims to answer are:

* Identify constitutional structural variants by OGM of DNA extracted from blood leukocytes of patients with DSD for which the molecular diagnosis is inconclusive.
* Identify mosaic structural variants (present in a subpopulation of somatic cells only) by OGM of DNA extracted from blood leukocytes of patients with DSD for which the molecular diagnosis is inconclusive.
* Compare the diagnostic yields of OGM and of Comparative Genome Hybridization Array (CGH array) methods.
* Compare the diagnostic yields of the OGM and of Whole Genome Sequencing (National Sequencing Program), only if performed.

Participants will be required to:

* a follow-up interview with a physician to review their own and family medical and surgical history, with a focusing on DSD.
* An interview to assess their exposure to environmental pollutants during fetal life, using a validated questionnaire.
* a blood test with a 5mL tube to perform optical genome mapping analysis.

Detailed description: Patients with severe or moderate disorder of sex development (DSD) with a inconclusive molecular diagnosis will benefit from optical genome mapping analysis.

A venous blood sample on ethylenediaminetetraacetic acid (EDTA) tube (5mL) will be taken in order to extract the DNA that will be used for the optical genome mapping analysis.

Eligibility criteria: Inclusion Criteria:

* homogeneous XY male karyotype.
* patient at least 6 months old
* severe to moderate DSD (Prader 1 to 5) for which the molecular diagnosis is inconclusive after a gene panel analysis.

Exclusion Criteria:

* subject with a homogeneous or mosaic XX, or monosomal X karyotype.
* subject with an aneuploidy.
* subject with a conclusive molecular diagnosis explaining the observed DSD (i.e. carrier of a causal genotype already well characterized by functional studies)

Primary outcomes:
measure: Number of Participants with a constitutional structural variants detected by OGM
timeFrame: Day of inclusion
Secondary outcomes:
measure: Number of Participants with mosaic structural variants detected by OGM
timeFrame: Day of inclusion
Other outcomes:
Locations:
city: Montpellier
country: France
facility: University Hospital Montpellier
Study officials:
affiliation: University Hospital, Montpellier
name: Françoise PARIS, MD PhD
role: PRINCIPAL_INVESTIGATOR
References: