High Depth Exome Sequencing on DNA From a Salivary Sample by Mouth Smear.
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: genetic.
- Who it may be relevant to
- Registry conditions: Neurodevelopmental Disorders, Intellectual Developmental Disorder. Basic parameters: No limits · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Official title
Evaluation of the Diagnostic Performance of High-depth Exome Sequencing on DNA From a Salivary Sample by Oral Smear in the Etiological Assessment of Patients With a Syndromic Neurodevelopmental Disorder or an Intellectual Development Disorder and for Which the Sequencing of the Genome on Blood Has Proved Inconclusive.
Overview
Despite technological advances, a genetic etiology has been identified in only about 50% to 60% of patients with Neurodevelopmental disorders (NDDs), with a higher diagnostic yield in the syndromic NDD and IDD subgroups. However, identifying a precise etiological diagnosis is essential to optimize patient care, clarify their prognosis, consider targeted therapies, refer families to appropriate resources and support, and provide genetic counseling to relatives. The tests typically offered as part of the etiological assessment of syndromic NDDs and IDD include DNA microarray analysis, testing for fragile X syndrome and genome sequencing from a blood sample. When this assessment remains negative, the cause usually remains unknown. Mosaic genomic abnormalities (or post-zygotic variations) are a common cause of negative results in current diagnostic genetic tests and represent a field of research that has yet to be fully explored outside of skin disorders. Identifying mosaic genomic abnormalities remains technically complex due to the difficulty of detecting low levels of mosaicism and limited access to the tissue of interest when the variation is absent from blood tissue. High-depth exome sequencing is the technique of choice for detecting low levels of mosaicism. In the case of NNDs, as the affected tissue is not available, the buccal epithelium is an interesting alternative to blood, as it is easily accessible and inexpensive. The objective of our study is to evaluate the diagnostic yield of high-depth exome sequencing technology on a DNA extracted from a buccal swab in the etiological assessment of patients with IDD or syndromic NDD whose reference analysis (genome sequencing on blood) proved inconclusive.
Interventions
- Diagnostic test genetic
buccal swab
Primary outcome measures
- Identification of a defined genetic cause by demonstrating at least one variation of class 4 (probably pathogenic) or 5 (pathogenic) according to the ACMG classification explaining the patient's symptoms. [Time frame: 2 years]
Eligibility criteria
Inclusion criteria
- Patient with syndromic neurodevelopmental disorder (NDD) or intellectual developmental disorder (IDD)
- Trio genome sequencing on blood inconclusive
- Men and women
- All ages
- No objection to participating in the study
- Affiliation with a French social security system or beneficiary of such a system
Exclusion criteria
- Pregnant women and nursing mothers
- Persons deprived of their liberty by judicial or administrative decision; persons undergoing compulsory psychiatric care; persons admitted to a health or social care facility for purposes other than research
- Subjects who are in the exclusion period of another study or listed in the "national volunteer registry"
- Genetic cause identified in the preliminary etiological assessment
- Phenocopy: other likely non-genetic cause of TND (perinatal anoxia, infection, trauma, etc.)
- Patients without health insurance
- Patients unlikely to cooperate with the study and/or anticipated low cooperation by the investigator
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Cohort
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT07492199 · 2026/1030