Clinical management of psychosis in 22q11.2 deletion syndrome

Schizophrenia and papillary thyroid carcinoma in an adolescent female with 22q11.2 deletion syndrome

22q11.2 deletion syndrome is a condition with complex multisystem involvement, and many clinicians will encounter patients living with the condition. 22q11.2 deletion syndrome is known to significantly increase the risk of psychosis, and there is some emerging evidence that 22q11.2 deletion syndrome may be associated with an increased risk of malignancy. We report on a case of an adolescent female who had a delayed diagnosis of 22q11.2 deletion syndrome after she developed severe psychosis at an early age. She was subsequently diagnosed in late adolescence with papillary thyroid carcinoma. This case contributes to the limited body of evidence regarding the treatment of psychosis secondary to 22q11.2 deletion syndrome and the potential increased risk of malignancy associated with the genetic condition.

Clozapine Use in 22q11.2 Deletion Syndrome: A Systematic Review of the Literature

BACKGROUND

22q11.2 deletion syndrome confers significant risk for the development of schizophrenia. While current recommendations regarding the management of psychotic symptoms in affected individuals are generally in keeping with treatment guidelines for general schizophrenia populations, evidence for the use of clozapine has come from case reports and retrospective observational data. As no reviews on the topic currently exist, a systematic review of clozapine use in 22q11.2 deletion syndrome was completed.

METHODS

In November 2023, a literature search was completed using both PubMed and Scopus to identify English-language articles that reported the use of clozapine in humans with 22q11.2 deletion syndrome.

RESULTS

Twenty-six articles describing 57 individuals were deemed eligible for inclusion. Most individuals had a diagnosis of treatment-resistant schizophrenia. Where reported, the mean or median dose of clozapine was relatively low, and the majority of individuals exhibited a good response (approximately 65.5% across individual case reports/series). While seizures were unsurprisingly the most commonly reported serious adverse effect, the majority of individuals were able to remain on (or be restarted on) clozapine by having their dose decreased and/or by adding an anticonvulsant (most commonly valproate).

CONCLUSIONS

This review reaffirms that individuals with 22q11.2 deletion syndrome may benefit from clozapine therapy even at a low dose, assuming they meet criteria for treatment-resistant schizophrenia and provided no contraindications exist. However, given the increased incidence of seizures in 22q11.2 deletion syndrome, the use of prophylactic anticonvulsant therapy should be considered, and hypoparathyroidism/hypocalcemia screened for and corrected before the initiation of clozapine. It is also recommended that clozapine blood levels be monitored.