Negative symptom scores and clinical course scores were significantly higher (worse) when paternally inherited, but there is also
evidence for anticipation suggesting the involvement of an unstable trinucleotide repeat (Ohara
K et al, 1997; O'Donovan MC et al, 1995; Valero
J et al, 1998; Bassett AS et al, 1994). Husted found that anticipation
was greater with paternal than with maternal transmission (Husted J et al, 1998). In contrast others have found no
evidence of true anticipation, or parental affect on transmission or age of onset (Asherson P et al, 1994;
DeLisi LE et al, 2000). Affected sibling pairs were more likely to be of the same sex when the history of schizophrenia was
on the paternal side (Crow TJ et al, 1989).
For a review of data that support an association between paternal factors and schizophrenia see Malaspina D, 2001.