Chromosome 22q11 deletions, velo-cardio-facial syndrome and early-onset psychosis. Molecular genetic study.
BACKGROUND
Velo-cardio-facial syndrome (VCFS) is associated with interstitial deletions of chromosome 22q11. About 30% of patients with VCFS have psychosis, and the rate of these deletions in schizophrenia has been reported to be about 1%. Even higher rates of VCFS deletions have been reported for childhood-onset schizophrenia.


OBJECTIVE
To test the hypothesis that there is an increased rate of VCFS among patients with early-onset psychosis (age at onset <18 years). We screened 192 early-onset patients and 329 patients with adult-onset schizophrenia.


METHODS
We genotyped the patients and 444 healthy controls for hemizygosity of five microsatellite markers and one single nucleotide polymorphism that map to the 22q11-deleted region.


RESULTS
One patient had a VCFS deletion, confirmed with semi-quantitative polymerase chain reaction. None of the controls showed a pattern of genotypes consistent with hemizygosity.


CONCLUSIONS
VCFS may be less frequent among patients with psychosis than previously suggested; this rate is not increased among early-onset patients.
Ivanov
D
D
Neuropsychiatric Genetics Unit, Department of Psychological Medicine, University of Wales College of Medicine, Cardiff, UK.
Kirov
G
G
Norton
N
N
Williams
H J
HJ
Williams
N M
NM
Nikolov
I
I
Tzwetkova
R
R
Stambolova
S M
SM
Murphy
K C
KC
Toncheva
D
D
Thapar
A
A
O'Donovan
M C
MC
Owen
M J
MJ
D000015:Abnormalities, Multiple / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001483:Base Sequence; D002648:Child; D002872:Chromosome Deletion; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D002972:Cleft Palate / Q000235:genetics; D005145:Face / Q000002:abnormalities*; D005260:Female; D005838:Genotype; D006330:Heart Defects, Congenital / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012559:Schizophrenia / Q000235:genetics*; D013577:Syndrome