Could lithium ease symptoms of rare Autism-Linked condition?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Written informed consent from the patient, parent or legal representative * ≥6 years old at the time of consent * Proven pathogenic or probably pathogenic TBR1 variant (SNV confirmed by Sanger sequencing or CNV including only TBR1) * If applicable: Stable concomitant psychoactive medication regimen (dose and schedule) ≥2 months prior to lithium initiation * Affected individuals able to take tablet /capsules orally * Highly effective method of contraception in affected female individuals of childbearing age (Combined hormonal contraception, progestogen-only hormonal contraception, intrauterine device, intrauterine hormone-releasing system or abstinence) during treatment and for at least 3 months after the final dose of lithium * Highly effective method of contraception in affected men individuals of childbearing age (condom or abstinence) during the treatment and for at least 5 days after the final dose of lithium * 1 available parent/guardian able to attend all visits having acceptable reading skills Exclusion Criteria: Criteria related to associated pathologies leading to particular risks: * Renal/liver insufficiency (disturbed liver function, abnormal creatinine clearance) * Unbalanced thyroid or diabetic pathology * Long QT/Brugada syndrome or familial antecedent of Brugada syndrome, cardiac insufficiency * Addison disease, dehydration, sodium restriction * Non-stabilized epileptic disease. Criteria related to contra-indication to treatment: * Patient with concomitant diseases for which the experimental treatment by lithium could alter the tolerance * Hypersensitivity to lactose, lithium or one of its excipients * Patient with a wheat allergy (other than celiac disease) * Pregnant or breastfeeding woman Criteria related to treatments/procedures: * Parent/guardian incapable of expressing consent * Person not affiliated to a national health insurance scheme * Person subject to a court order * Cognitivo-behavioural therapy focused on ASD in 6 weeks previous to inclusion * Other genetic pathogenic variant associated to neurocognitive disorders * Any introduction of psychotropic molecules within 2 months prior to the trial, including neuroleptics, monoamine oxidase inhibitors, stimulants, antidepressants. * Concomitant use of Angiotensin-Converting Enzyme (ACE) inhibitor, angiotensin II receptor antagonists, Nonsteroidal anti-inflammatory drugs, diuretics. * Current lithium treatment * Severe behavioural disorder or refusal to take drug treatment not allowing for compliance with medication; * Impossibility to perform blood tests to check the lithiaemia when the patient is included. * Participation in another therapeutic trial