Obsessive‐compulsive symptom dimensions in affected sibling pairs diagnosed with Gilles de la Tourette syndrome

Abstract

Obsessive-compulsive disorder (OCD) is an etiologically heterogeneous disorder. Recent factor analyses have consistently identified several symptom dimensions, two of which are associated with increased familial risk for OCD; aggressive, sexual, and religious obsessions and checking compulsions (FACTOR 1) and symmetry and ordering obsessions and compulsions (FACTOR 2). Both of these symptom dimensions are also frequently seen in association with Gilles de la Tourette syndrome (GTS). The purpose of this study was to determine whether these obsessive-compulsive (OC) symptom dimensions are correlated within families (between sibs and between parent-child pairs). Using data collected by the Tourette Syndrome Association International Consortium for Genetics Affected Sibling Pair Study, the authors selected all available GTS sib pairs and their parents for which these OC symptom dimensions (factor scores) could be generated. This group included 128 full sibs and their mothers (54) and fathers (54). Four OC symptom dimension scores were computed for each family member using an algorithm derived from item endorsements from the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) symptom checklist. In addition to a series of univariate analyses, complex segregation analyses were also completed using these quantitative OC symptom dimension scores. FACTOR 1 and FACTOR 2 scores were significantly correlated in sib pairs concordant for GTS. The mother-child correlations, but not father-child correlations, were also significant for these two factors. Segregation analyses were consistent with dominant major gene effects for both FACTOR 1 and FACTOR 2. We conclude that familial factors contribute significantly to OC symptom dimension phenotypes in GTS families. This familial contribution could be genetic or environmental.

Heritability of obsessive‐compulsive symptom dimensions

“…These results support the findings of some of the family studies investigating the familiality of OC symptom dimensions, based on Y-BOCS items [Leckman et al, 2003;Hasler et al, 2007]. Hasler et al [2007] found significant sib-sib correlations for Checking compulsions and the Contamination/ Cleaning dimension.…”

“…They reported that the relatives of OCD probands who had high scores on either the YaleBrown Obsessive-Compulsive Scale (Y-BOCS) factors ''aggressive/sexual/religious obsessions and related compulsions'' or ''symmetry/ordering'' were twice as likely to have first-degree family members with OCD compared to individuals with low scores on these factors. Leckman et al [2003] examined the familiality of OC symptom dimensions in sib pairs affected with Tourette syndrome. Significant correlations were observed between sib pairs as well as mother-child pairs for the ''aggressive/sexual/religious obsessions and checking compulsions'' factor, and for the ''symmetry/ordering obsessions and compulsions'' factor.…”

Further development of YBOCS dimensions in the OCD Collaborative Genetics Study: Symptoms vs. categories

“…The significant sib-sib association for the Taboo Thoughts factor is consistent with the findings of two prior segregation analyses (Alsobrook et al, 1999;Leckman et al, 2003), though those studies used the Leckman et al (1997) factor which also includes somatic obsessions and checking compulsions. As compared to the r ICC for Taboo Thoughts in the present study, Hasler et al (2007) reported a lower, yet still statistically significant, sib-sib correlation for their more heterogeneous obsessions/checking factor (same as the Leckman et al (1997) factor).…”

“…Alsobrook et al (1999) reported that the recurrence risk of OCD among first-degree relatives of probands with high scores on either the obsessions/ checking or symmetry/ordering factors was much higher than the recurrence risk among relatives of probands with low scores on these factors. In a segregation analysis, Leckman et al (2003) yielded significant correlations between siblings and mother-child pairs for the same two factors in a sample of Tourette Syndrome affected sibpairs and relatives. Cullen et al (2007) examined affected sibling similarity on four DFA-derived category-based factors in the Johns Hopkins OCD Family Study.…”

A Large Case–Control Study of Common Functional SLC6A4 and BDNF Variants in Obsessive–Compulsive Disorder

“…It is thought that the diverse phenomenological and treatment presentation of this disorder may reflect, in turn, a heterogeneity of susceptibility genes. Attempts at better defining more homogeneous OCD subgroups have been made at the level of symptom presentation (Hasler et al, 2006), age of OCD onset (Shugart et al, 2006), family history (Denys et al, 2006), and comorbidity patterns (Leckman et al, 2003). Despite the theoretical plausibility of these subgroups, studies assessing candidate genes in light of more unified OCD sub-phenotypes have also been marked by inconclusive findings and a lack of replication.…”