Further studies on a male monozygotic triplet with schizophrenia: cytogenetical and neurobiological assessments in the patients and their parents.

We previously described a Swedish set of male schizophrenic monozygotic triplets. In this study the patients as well as their parents were further characterized. By high-resolution chromosomal analysis an extra band at chromosome 15p was found in all the triplets and the father. Microdissection, degenerate oligonucleotide-primed PCR (DOP-PCR) amplification and reverse painting indicates that the extra band probably contains only repetitive DNA sequences with no known effect on the phenotype. Magnetic resonance imaging (MRI) showed similar borderline ventricular enlargement and widened subarachnoid spaces over frontoparietal and basal regions as well as around the pituitary gland (empty sella) in all the triplets. The father also had widened subarachnoid spaces over the frontal and basal regions. The mother had an empty sella indicating widened subarachnoid spaces. All the boys also had a right-sided conductive hearing defect, probably due to malformation and fixation of the ossicular chain. The parents did not present any otological abnormalities. Neuropsychological assessment demonstrated similar marked reductions of attentional, mnestic, and executive functions in all the triplets, but the mother showed a normal pattern. Possible joint etiological mechanisms for the psychological and somatic abnormalities recorded in the triplets are discussed.