Parent-of-origin effect in panic disorder

Parent-of-origin effect was examined in a series of 64 pedigrees with panic disorder (PD) under both the narrow and broad diagnostic models. The narro w diagnostic model defined the affected phenotype to include only the "defi nite" and "probable" forms of PD, whereas the broad diagnostic model includ ed the entire PD symptomatology, The pattern of maternal vs. paternal trans mission of disease was analyzed through a number of comparisons, These comp arisons were performed first on all pedigrees and then on a subset of "pure " pedigrees including only strictly maternal transmission or strictly pater nal transmission of PD, There were no significant differences in the propor tion of offspring born to transmitting mothers vs. transmitting fathers und er either diagnostic model or pedigree set. When the difference in the sex ratio among affected offspring from both transmission types was considered, only the "pure" pedigree sample under the broad diagnostic model yielded n ominally (i.e., not corrected for multiple tests) significant results (P < .05), Also, the comparisons of cumulative lifetime risk for PD between offs pring of transmitting mothers and fathers gave some nominally significant r esults; when affected and unaffected offspring were considered, significant results were observed under the narrow and broad diagnostic models, P < .0 005 and P < .05, respectively. These findings must be considered provisiona l until confirmed by further study. (C) 1999 Wiley-Liss, Inc.