Am J Psychiatry 1996; 153:1166-1172
Copyright © 1996 by American Psychiatric Association
Prenatal growth markers in schizophrenia: a monozygotic co-twin control study
JO Davis and HS Bracha
Department of Psychology, Southwest Missouri State University, Springfield 65804-0095, USA.
OBJECTIVE: This co-twin study investigated monozygotic twins who were
discordant for schizophrenia for evidence of prenatal growth differences
between the affected and well co-twins. METHOD: Four dermatoglyphic markers
of prenatal growth were obtained by established procedures from 26
monozygotic twin pairs discordant for schizophrenia, 13 monozygotic twin
pairs concordant for schizophrenia, and several normal monozygotic twin
samples. RESULTS: The a-b ridge count differences between the affected and
well co-twins were greater than those found for concordant and normal
monozygotic pairs. In comparison with their well co-twins, the affected
twins, in discordant pairs, had developed fewer epidermal ridges in the a-b
interdigital area of their right palms. In contrast, no significant
differences were found between the affected twins and their well co-twins
on markers associated with fetal development before 13 or after 15 weeks
estimated gestational age. CONCLUSIONS: Because the a-b ridges are known to
complete development between 13 and 15 weeks estimated gestational age, the
results provide physical evidence suggesting that the schizophrenia-
affected monozygotic twins alone experienced a time-specific and time-
limited dysgenesis during this time. Commonalities in the ontogeny of
epidermal and neurological structures are discussed.
