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Metyrosine in Adolescent Psychosis Associated with 22q11.2 Deletion Syndrome

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"Metyrosine in Adolescent Psychosis Associated with 22q11.2 Deletion Syndrome,"
Halifax, Nova Scotia, Canada; June 7, 2006
Dalhousie University, Department of Psychiatry, Clinical Conference
*Learn clinical features of velocardiofacial syndrome (VCFS)
*Learn association of psychosis with VCFS
*Learn genetic and biochemical abnormalities leading to psychosis in VCFS
*Discuss case report of metyrosine in psychosis associated with VCFS
*What can we learn from the association between VCFS and schizophrenia to design candidate gene studies for polygenic syndromes?

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Metyrosine in Adolescent Psychosis Associated with 22q11.2 Deletion Syndrome

  1. 1. Metyrosine in Adolescent Psychosis Associated With 22q11.2 Deletion Syndrome Carlo G. Carandang, MD, DABPN Mood Disorders Group IWK Health Centre
  2. 2. Disclosures Research Support: GlaxoSmithKline (USA) Other Financial Disclosures: None
  3. 3. Objectives Learn clinical features of velocardiofacial syndrome (VCFS) Learn association of psychosis with VCFS Learn genetic and biochemical abnormalities leading to psychosis in VCFS Discuss case report of metyrosine in psychosis associated with VCFS What can we learn from the association between VCFS and schizophrenia to design candidate gene studies for polygenic syndromes?
  4. 4. Case Report Carandang C and Scholten M (in press, 2006). Metyrosine in Psychosis Associated with 22q11.2 Deletion Syndrome: A Case Report. Journal of Child and Adolescent Psychopharmacology.
  5. 5. Velocardiofacial Syndrome (VCFS) First described by Robert Shprintzen in 1978 From Latin words Velum = palate Cardia = heart Facies = face Recent literature uses nomenclature denoting genetic deletion: 22q11.2 Deletion Syndrome (22q11.2 DS) VCFS also known as: Shprintzen Syndrome, DiGeorge Syndrome, Craniofacial Syndrome, or Conotruncal Anomaly Unusual Face Syndrome
  6. 6. Velocardiofacial Syndrome (VCFS) Not uncommon Prevalence 1 in every 4,000 newborns 8% of all cleft palate patients
  7. 7. VCFS Is a Risk Factor for Schizophrenia Prevalence of schizophrenia among patients with VCFS ranges from 10% to 30% (Shprintzen et al. 1992, Pulver et al. 1994, Murphy et al. 1999) Amongst those with schizophrenia, prevalence of VCFS ranges from 1% to 2% (Horowitz et al. 2005, Murphy 2002, Karayiorgou et al. 1995)
  8. 8. VCFS Clinical Features Clinical Features Cleft palate Heart defects Characteristic facies Hypernasal speech Learning disabilities
  9. 9. Velocardiofacial Syndrome (VCFS) Facial Findings: • Elongated face • Almond-shaped eyes • Wide nose • Small ears Pictures From: Shprintzen RJ: Velocardiofacial Syndrome. Otolaryngol Clin North Am 33(6), 2000.
  10. 10. VCFS Results from hemizygous deletion of the long arm of chromosome 22, spanning 22 well-characterized genes, including COMT gene Only 10% of cases are inherited For other 90%, cause of deletion unknown Diagnosis confirmed by fluorescence in situ hybridization (FISH)
  11. 11. TBX-1 (T-box transcription factor) CRKL UFD1L (Ubiquitination degradation) HIRA(transcription factor) Centromere DGCR6 IDD/DGCR2 TSK/DGS-G ES2/DGS1 GSCL (Goosecoid-like homeobox gene) CTP (Citrate transporter) CLTCL TMVCF CDCrel-1 GP1b (Platelet glycoprotein) T10 COMT (Catechol-O-methyltransferase) ARVCF LZTR-1 (Transcriptionfactor) ZNF74 CDC45L RANBP1 Human Ch22q11.2 Heparin cofactor 90% 8%
  12. 12. Psychosis and VCFS Hypothesized that psychosis associated with 22q11.2 deletion syndrome may be associated with excess catecholamines from a functional deficiency of catechol-O-methyltransferase (COMT) Deficiency of COMT could result from either or both: Half-dose expression (only one copy of allele) Presence of low-activity COMT variant on the non- deleted allele
  13. 13. Metyrosine (Demser®) A key step in the biosynthesis of dopamine involves the conversion of tyrosine to dihydroxyphenylalanine (DOPA) This rate-limiting step is catalyzed by the enzyme tyrosine hydroxylase The catalytic conversion is blocked by the competitive inhibitor, α-methyltyrosine (metyrosine)
  14. 14. Metyrosine (Demser®) Metyrosine competitively inhibits the enzyme tyrosine hydroxylase Inhibition of tyrosine hydroxylase leads to decrease of dopamine levels and reduction of psychotic symptoms Psychosis associated VCFS are relatively unresponsive to currently used antipsychotics (Graf et al. 2001, Gothelf et al. 1999)
  15. 15. Intervention Studies of VCFS Psychosis Graf et al. 2001, case series, N=5 Metyrosine was effective in reducing neuropsychiatric symptoms in 4 patients Carandang and Scholten, 2006 (in press), case report Metyrosine effective in treating psychosis resistant to antipsychotics
  16. 16. Case Report 15 year-old male presents for 1st psych hospitalization Diagnosed VCFS in early childhood RFA: Aggression towards mother Multiple mood symptoms lasting months Mood lability, tearfulness, hypersomnia, social withdrawal, apathy, and declining school performance
  17. 17. Case Report While in NYC, ran away for 2 days on the subway After NYC trip, convinced he will be miserable if he lives with his parents in the countryside, and would be happy if he lived in a big city Threatened mother with knife, as she was a barrier to his moving to the big city
  18. 18. Case Report Early childhood: speech and motor delays Age 4, problems with attention: a trial of methylphenidate led to a negative reaction Elementary school: problems processing multi-step directions Recent testing: verbal IQ 85, performance IQ 83
  19. 19. Case Report Premorbid functioning otherwise normal average student, friendly and affectionate person VCFS confirmed by FISH age 12 Hypernasal speech, typical facies, learning deficits No other medical problems 2 paternal first cousins and a maternal aunt had mood disorders
  20. 20. Case Report Additional Symptoms: Poor hygiene, poor eye contact, dysarthria, non-spontaneous/telegraphic speech, affect blunted, guarded, and exhibited significant mood lability. Thought processes were concrete. No loosening of associations were noted. He perseverated on moving to the big city DDx: prodromal schizophrenia vs. mood disorder
  21. 21. Case Report Psychosis Clinic: Structured Interview for Prodromal Syndromes (SIPS) Scoring of the SIPS was in the psychotic range with regards to the unusual thought content While his belief about “moving to the big city to be happy” was not the bizarre or typical beliefs associated with psychosis, the patient held this belief with unwavering conviction and had acted on this belief in aggressive and risky ways. His pervasive thoughts also affected his academic, social, and family functioning. Patient had minimal insight into the seriousness of his dangerous behaviors.
  22. 22. Case Report However, the clinicians and researchers in the psychosis specialty clinic had difficulty giving a diagnosis of psychosis (despite the scoring on the SIPS), as this was an atypical presentation for psychosis. Nonetheless, the working diagnosis was Psychotic Disorder NOS, with the differential including prodromal psychosis and Delusional Disorder.
  23. 23. Case Report In the ensuing months, patient endured multiple psychiatric hospitalizations 2nd psych hosp was for suicide attempts Aripiprazole (Abilify®) was started and titrated to 10mg daily. The patient initially responded, as he was less labile, less withdrawn, and more animated. Discharged on aripiprazole
  24. 24. Case Report Readmitted the next month for his third hospitalization for self-harm behaviors, and eventually discharged. 1 month later, behaviors again worsened. He had been making excessive attempts to communicate with his friend, which prompted a call from the friend’s parents to the patient’s parents. Precipitated a rapid decompensation, where the patient barricaded himself in his room and cut both his forearms.
  25. 25. Case Report Police were summoned to escort the patient to the hospital (4th hospitalization) When police arrived, the patient attempted to stab the officer with a knife, who blocked the attempt and disarmed the patient. Parents had never seen this level of aggression with their son, and opined that the treatment with aripiprazole worsened his symptoms.
  26. 26. Case Report Inpatient attending consulted with an expert on VCFS. The expert recommended a trial of metyrosine (Demser®), as many patients with VCFS have a COMT deficiency. Aripiprazole was discontinued and metyrosine was titrated to 1750mg daily. The patient had significant response to metyrosine, as he exhibited less mood lability and was less perseverative on his belief of moving to the big city to be happy. He was discharged on a maintenance dose of metyrosine 1000mg daily, and exhibited significant functional improvement.
  27. 27. Case Report While on metyrosine, the patient was able to avoid hospitalization, attend school, and engage in relationships with family and friends. Patient reported improved moods, less irritability, and denied fixed ideations. In addition, he no longer believed that it was absolutely necessary for him to live in the big city to be happy. Continued to function on metyrosine for over 1 year, at which time he was transferred to another psychiatrist.
  28. 28. (Carandang and Scholten, in press, 2006) Innovative “The treatment of metyrosine for VCFS psychosis represents a first in psychiatry, where a known biochemical abnormality in a psychiatric disorder was corrected by a treatment that targets the biochemical pathway, leading to reduction of psychiatric symptoms.” “Treatment of a specific biochemical consequence of a genetic variation is important not only for the treatment of a specific group of patients, but as a model for elucidating the genetic correlates of psychiatric disorders.”
  29. 29. Oligogenic Disorders and Polygenic Syndromes • Oligogenic diseases (scientifically interesting but not major public health problems) • Williams syndrome • Fragile X • Tuberous sclerosis • Velo-cardio-facial syndrome • Polygenic syndromes (important CNS disorders with more variable genetic causes and brain/behavioural phenotypes) • Schizophrenia • Bipolar Affective Disorder • Stroke
  30. 30. How Can We Design Candidate Gene Studies for Polygenic Syndromes? Study an oligogenic disorder which mimics the polygenic syndrome VCFS with psychosis mimics schizophrenia Study known polymorphisms leading to biochemical deficits associated with the oligogenic disorder COMT gene
  31. 31. Summary Rule-out VCFS in psychosis evaluations, especially if the patient has two or more features of the syndrome and does not respond to antipsychotic medication. Definitive diagnosis obtained with FISH. Consider Metyrosine for VCFS psychosis not responsive to antipsychotics.
  32. 32. IWK Mood Disorders Group: Collaborators Suzanne Zinck, MD Darcy Santor, PhD Mark Samuels, PhD (Maritime Medical Genetics)

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