Download Why is Exotropia (one Specific Type of Strabismus) Associated with

Why is Exotropia (one Specific Type of Strabismus) Associated with Schizophrenia?
Christopher S. von Bartheld1, Andrea B. Agarwal1, Cheng-yuan Feng1, Austin J. Christensen1,
Dan Wen2, Kellie Cassinelli 3, L. Alan Johnson1,3, Brian Kirkpatrick4
1
Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno,
NV
2
Department of Ophthalmology, Xiangya Hospital, Central South University, China
3
Sierra Eye Associates, Reno, NV
4
Department of Psychiatry and Behavioral Sciences, University of Nevada School of Medicine,
Reno, NV
Background/Objective. Children with one type of strabismus, exotropia, have an increased risk
of developing schizophrenia. We determined whether schizophrenia biomarkers have altered
levels of gene expression in strabismic eye muscles that may explain the link with exotropia. We
also determined whether the known seasonality of births among people with schizophrenia is
matched by births in patients with strabismus.
Methods. Gene expression differences on customized PCR arrays were compiled from paired
comparisons and birth records from 4,847 strabismic patients were analyzed.
Results. Among 381 genes encoding signaling molecules, 22 were significantly altered in
strabismic medial rectus muscles, ten of which were known biomarkers for schizophrenia.
Altered expression of schizophrenia-related genes was similarly found in lateral rectus muscles.
The pattern of births in exotropia, but not esotropia, was positively correlated with the pattern of
births previously established for people with the deficit type of schizophrenia, but not
schizophrenia as a whole.
Discussion/Conclusions. Our data indicate that gene expression changes are not specific for
exotropia and that exotropia may be associated primarily with the deficit type of schizophrenia.
Supported by NIGMS grants GM104944 and GM103554.