High Depth Exome Sequencing on DNA From a Salivary Sample by Mouth Smear.

NCT07492199 | Not Yet Recruiting

• 1 other identifier: 2026/1030
• Study Type: observational
• Target: 50
• Locations: 0 countries
• Sites: N/A

Brief Summary

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.

Conditions

Neurodevelopmental Disorders; Intellectual Developmental Disorder

Outcome Measures

Primary Outcomes (1)

• 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.

  2 years

Interventions

genetic DIAGNOSTIC_TEST

buccal swab

Eligibility Criteria

• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Men and women of all ages with syndromic neurodevelopmental disorder (NDD) or intellectual developmental disorder (IDD) and a trio genome sequencing on blood inconclusive

You may qualify if:

• 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

You may not qualify if:

• 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
• 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

Sponsors & Collaborators

• Centre Hospitalier Universitaire de Besancon: lead

MeSH Terms

Conditions

Neurodevelopmental Disorders; Intellectual Disability

Condition Hierarchy (Ancestors)

Mental Disorders; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Juliette PIARD, Pr

CONTACT

33381218187; jpiard@chu-besancon.fr

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 19, 2026
• First Posted: March 25, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): April 1, 2028
• Study Completion (Estimated): April 1, 2029
• Last Updated: April 14, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share