clozapine and Chromosome-Deletion

22q11.2 deletion is the most common microdeletion in humans and one of the most important risk factors for schizophrenia. Nevertheless, case reports of children or adolescents with 22q11.2 deletion and schizophrenia are very rare. After a review of the current knowledge about physical, developmental, behavioural and psychiatric problems in 22q11.2 deletion, the case of a 12;10-year-old boy with schizophrenia and the microdeletion is reported. About three years after the first symptoms, and only after medication with several neuroleptics, the patient reached his pre-morbid functioning level under treatment with risperidone. Under medication with clozapine he had experienced a single event of seizures which were due to hypocalcemia. This case report illustrates the importance of serum calcium controls at regular intervals for patients with 22q11.2 deletion and schizophrenia who are on neuroleptic medication. Ideally, children and adolescents with the deletion and co-morbid psychiatric problems should be treated in child and adolescent psychiatry units specialized in problems associated with the deletion. A good cooperation with other medical services is absolutely necessary.

Topics: Adolescent; Antipsychotic Agents; Calcium; Child; Chromosome Deletion; Chromosomes, Human, Pair 22; Clozapine; Developmental Disabilities; Female; Follow-Up Studies; Genetic Predisposition to Disease; Humans; Hypocalcemia; Male; Risperidone; Schizophrenia; Schizophrenic Psychology; Seizures

Human chromosome 22q11.2 has been implicated in various behavioral abnormalities, including schizophrenia and other neuropsychiatric/behavioral disorders. However, the specific genes within 22q11.2 that contribute to these disorders are still poorly understood. Here, we show that an approximately 200-kb segment of human 22q11.2 causes specific behavioral abnormalities in mice. Mice that overexpress an approximately 200-kb region of human 22q11.2, containing CDCrel, GP1Bbeta, TBX1, and WDR14, exhibited spontaneous sensitization of hyperactivity and a lack of habituation. These effects were ameliorated by antipsychotic drugs. The transgenic mice were also impaired in nesting behavior. Although Tbx1 has been shown to be responsible for many physical defects associated with 22q11.2 haploinsufficiency, Tbx1 heterozygous mice did not display these behavioral abnormalities. Our results show that the approximately 200-kb region of 22q11.2 contains a gene(s) responsible for behavioral abnormalities and suggest that distinct genetic components within 22q11.2 mediate physical and behavioral abnormalities.

Topics: Abnormalities, Multiple; Amphetamines; Animals; Antipsychotic Agents; Behavior, Animal; Chromosome Deletion; Chromosomes, Human, Pair 22; Clozapine; Disease Models, Animal; Female; Heterozygote; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Psychotic Disorders; Schizophrenia; Time Factors