Eye-tracking dysfunction (ETD) in families with sporadic and familial schizophrenia.
BACKGROUND
Within the field of genetic schizophrenia research, eye-tracking dysfunction can be regarded as a putative trait marker in families with multiple occurrences of the disease (familial schizophrenia). We concentrated on families with single occurrences of schizophrenia (sporadic schizophrenia) to test whether a genetic factor may be present in these families as well.


METHODS
Eye movements were recorded using infrared oculography in eight families with sporadic schizophrenia (44 members), eight families with familial schizophrenia (66 members), and nine nonpsychotic families (77 members). Triangle-wave stimuli at 15 degrees /sec and 30 degrees /sec were used, and gains (eye velocity/target velocity), rates, and amplitudes of saccades (classified as catch-up and anticipatory saccades) were determined.


RESULTS
1) In sporadic-schizophrenia families, gain values, saccade rates, and anticipatory saccade amplitudes at 30 degrees /sec differed in a statistically significant fashion from nonpsychotic families, but not from families with multiple occurrences of schizophrenia, and 2) at 30 degrees /sec, a significant effect of target direction on smooth-pursuit maintenance was observed in both sporadic- and familial-schizophrenia families.


CONCLUSIONS
Our results support the hypothesis that genetic factors may be present even in sporadic-schizophrenia families and may contribute to a more precise and biologically based definition of the schizophrenia phenotype in future molecular genetic analysis.
Lencer
R
R
Department of Psychiatry, University of Lübeck School of Medicine, Lübeck, Germany.
Malchow
C P
CP
Trillenberg-Krecker
K
K
Schwinger
E
E
Arolt
V
V
D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D004585:Electrooculography; D005133:Eye Movements / Q000235:genetics; D005191:Family Characteristics; D005260:Female; D007839:Functional Laterality; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011698:Pursuit, Smooth / Q000235:genetics*; D012438:Saccades / Q000235:genetics; D012559:Schizophrenia / Q000235:genetics* / Q000503:physiopathology*
D005819:Genetic Markers