Genetic and phenotypic overlap of specific obsessive-compulsive and attention-deficit/hyperactive subtypes with Tourette syndrome

BACKGROUND

The unique phenotypic and genetic aspects of obsessive-compulsive (OCD) and attention-deficit/hyperactivity disorder (ADHD) among individuals with Tourette syndrome (TS) are not well characterized. Here, we examine symptom patterns and heritability of OCD and ADHD in TS families.

METHOD

OCD and ADHD symptom patterns were examined in TS patients and their family members (N = 3494) using exploratory factor analyses (EFA) for OCD and ADHD symptoms separately, followed by latent class analyses (LCA) of the resulting OCD and ADHD factor sum scores jointly; heritability and clinical relevance of the resulting factors and classes were assessed.

RESULTS

EFA yielded a 2-factor model for ADHD and an 8-factor model for OCD. Both ADHD factors (inattentive and hyperactive/impulsive symptoms) were genetically related to TS, ADHD, and OCD. The doubts, contamination, need for sameness, and superstitions factors were genetically related to OCD, but not ADHD or TS; symmetry/exactness and fear-of-harm were associated with TS and OCD while hoarding was associated with ADHD and OCD. In contrast, aggressive urges were genetically associated with TS, OCD, and ADHD. LCA revealed a three-class solution: few OCD/ADHD symptoms (LC1), OCD & ADHD symptoms (LC2), and symmetry/exactness, hoarding, and ADHD symptoms (LC3). LC2 had the highest psychiatric comorbidity rates (⩾50% for all disorders).

CONCLUSIONS

Symmetry/exactness, aggressive urges, fear-of-harm, and hoarding show complex genetic relationships with TS, OCD, and ADHD, and, rather than being specific subtypes of OCD, transcend traditional diagnostic boundaries, perhaps representing an underlying vulnerability (e.g. failure of top-down cognitive control) common to all three disorders.

Autism Spectrum Symptoms in a Tourette's Disorder Sample

OBJECTIVE

Tourette's disorder (TD) and autism spectrum disorder (ASD) share clinical features and possibly an overlapping etiology. The aims of this study were to examine ASD symptom rates in participants with TD, and to characterize the relationships between ASD symptom patterns and TD, obsessive-compulsive disorder (OCD), and attention-deficit/hyperactivity disorder (ADHD).

METHOD

Participants with TD (n = 535) and their family members (n =234) recruited for genetic studies reported TD, OCD, and ADHD symptoms and completed the Social Responsiveness Scale Second Edition (SRS), which was used to characterize ASD symptoms.

RESULTS

SRS scores in participants with TD were similar to those observed in other clinical samples but lower than in ASD samples (mean SRS total raw score = 51; SD = 32.4). More children with TD met cut-off criteria for ASD (22.8%) than adults with TD (8.7%). The elevated rate in children was primarily due to high scores on the SRS Repetitive and Restricted Behaviors (RRB) subscale. Total SRS scores were correlated with TD (r = 0.27), OCD (r = 0.37), and ADHD (r = 0.44) and were higher among individuals with OCD symptom-based phenotypes than for those with tics alone.

CONCLUSION

Higher observed rates of ASD among children affected by TD may in part be due to difficulty in discriminating complex tics and OCD symptoms from ASD symptoms. Careful examination of ASD-specific symptom patterns (social communication vs. repetitive behaviors) is essential. Independent of ASD, the SRS may be a useful tool for identifying patients with TD with impairments in social communication that potentially place them at risk for bullying and other negative sequelae.

Identification of Two Heritable Cross-Disorder Endophenotypes for Tourette Syndrome

OBJECTIVE

Phenotypic heterogeneity in Tourette syndrome is partly due to complex genetic relationships among Tourette syndrome, obsessive-compulsive disorder (OCD), and attention deficit hyperactivity disorder (ADHD). Identifying symptom-based endophenotypes across diagnoses may aid gene-finding efforts.

METHOD

Assessments for Tourette syndrome, OCD, and ADHD symptoms were conducted in a discovery sample of 3,494 individuals recruited for genetic studies. Symptom-level factor and latent class analyses were conducted in Tourette syndrome families and replicated in an independent sample of 882 individuals. Classes were characterized by comorbidity rates and proportion of parents included. Heritability and polygenic load associated with Tourette syndrome, OCD, and ADHD were estimated.

RESULTS

The authors identified two cross-disorder symptom-based phenotypes across analyses: symmetry (symmetry, evening up, checking obsessions; ordering, arranging, counting, writing-rewriting compulsions, repetitive writing tics) and disinhibition (uttering syllables/words, echolalia/palilalia, coprolalia/copropraxia, and obsessive urges to offend/mutilate/be destructive). Heritability estimates for both endophenotypes were high and statistically significant (disinhibition factor=0.35, SE=0.03; symmetry factor=0.39, SE=0.03; symmetry class=0.38, SE=0.10). Mothers of Tourette syndrome probands had high rates of symmetry (49%) but not disinhibition (5%). Polygenic risk scores derived from a Tourette syndrome genome-wide association study (GWAS) were significantly associated with symmetry, while risk scores derived from an OCD GWAS were not. OCD polygenic risk scores were significantly associated with disinhibition, while Tourette syndrome and ADHD risk scores were not.

CONCLUSIONS

The analyses identified two heritable endophenotypes related to Tourette syndrome that cross traditional diagnostic boundaries. The symmetry phenotype correlated with Tourette syndrome polygenic load and was present in otherwise Tourette-unaffected mothers, suggesting that this phenotype may reflect additional Tourette syndrome (rather than OCD) genetic liability that is not captured by traditional DSM-based diagnoses.

Whole-genome association analysis of treatment response in obsessive-compulsive disorder

Up to 30% of patients with obsessive-compulsive disorder (OCD) exhibit an inadequate response to serotonin reuptake inhibitors (SRIs). To date, genetic predictors of OCD treatment response have not been systematically investigated using genome-wide association study (GWAS). To identify specific genetic variations potentially influencing SRI response, we conducted a GWAS study in 804 OCD patients with information on SRI response. SRI response was classified as 'response' (n=514) or 'non-response' (n=290), based on self-report. We used the more powerful Quasi-Likelihood Score Test (the MQLS test) to conduct a genome-wide association test correcting for relatedness, and then used an adjusted logistic model to evaluate the effect size of the variants in probands. The top single-nucleotide polymorphism (SNP) was rs17162912 (P=1.76 × 10(-8)), which is near the DISP1 gene on 1q41-q42, a microdeletion region implicated in neurological development. The other six SNPs showing suggestive evidence of association (P<10(-5)) were rs9303380, rs12437601, rs16988159, rs7676822, rs1911877 and rs723815. Among them, two SNPs in strong linkage disequilibrium, rs7676822 and rs1911877, located near the PCDH10 gene, gave P-values of 2.86 × 10(-6) and 8.41 × 10(-6), respectively. The other 35 variations with signals of potential significance (P<10(-4)) involve multiple genes expressed in the brain, including GRIN2B, PCDH10 and GPC6. Our enrichment analysis indicated suggestive roles of genes in the glutamatergic neurotransmission system (false discovery rate (FDR)=0.0097) and the serotonergic system (FDR=0.0213). Although the results presented may provide new insights into genetic mechanisms underlying treatment response in OCD, studies with larger sample sizes and detailed information on drug dosage and treatment duration are needed.

Familiality of Quantitative Autism Traits

Background:

Autistic traits exist along a continuum that extends into social functioning in the general population, and they aggregate in the family members of children with autism spectrum disorder (ASD). Quantitative measures are therefore essential when investigating the patterns of familiality of these traits. Prior studies have suggested differential inheritance patterns of autistic traits that depend on the cognitive level of the child with ASD as well as the family type.

Objective:

Our goal was to examine the family patterns of quantitative autism traits (QAT) in a group of simplex autism families of high-functioning children with ASD.

Method:

We used the Social Responsiveness Scale (SRS) to evaluate QAT in 47 ASD families and 46 control families. SRS assessments (parental/spousal evaluations) were collected for the children with ASD, their siblings, and their parents as well as for the control children and their parents.

Results:

The SRS was able to distinguish individuals with ASD from the control children and from their unaffected siblings. Significant group differences were also found when comparing the fathers of ASD families to control fathers and when comparing the brothers of individuals with ASD to control boys, with male members of ASD families having higher SRS scores. Gender differences were observed in the group of siblings of children with ASD and the group of parents of children with ASD, with males having higher scores than females. In ASD families, a positive trend between child and father QAT was found, whereas mothers’ scores were not associated with child outcomes. By contrast, in control families, mothers’ QAT correlated more strongly with child QAT.

Conclusions:

Autistic traits aggregate in the fathers and brothers of children with ASD in simplex autism families. The QAT levels of the family members should be taken into consideration when planning the rehabilitation of the child or adolescent with ASD and when designing family interventions.

A family study of trichotillomania and chronic hair pulling

Little is known about the etiology of hair pulling (HP) and its relationship to other obsessive compulsive (OC) spectrum disorders. In a large-sample family study, we examined the familial aggregation of HP and co-transmission of obsessive compulsive disorder (OCD) and skin picking (SP). Our sample consisted of 110 proband cases with HP and 48 controls without HP, plus 128 first-degree case relatives and 50 first-degree control relatives. Case versus control relatives had higher recurrence risk estimates for both HP and OCD but not SP. The finding that HP is familial is consistent with the only existing twin study. Additional analyses suggest that there may be a familial subtype of HP with comorbid OCD. Those adult proband cases with HP + OCD had more anxiety and depression than cases without OCD. Probands with HP + OCD also had earlier onset of OCD. Identification of an HP subtype with comorbid OCD may have significant theoretical and treatment implications. The data did not provide evidence for an etiologic relationship between HP and SP. Replication of these findings in future studies with larger cohorts of case and control relatives is warranted.

Social anxiety in parents of high-functioning children with autism and Asperger syndrome

We evaluated social anxiety (SA) symptoms in parents of children with autism spectrum disorders (ASDs; N = 131) and community parents (N = 597) using the Social Phobia and Anxiety Inventory (SPAI). SA was significantly more common in ASD than control mothers (15.6 vs. 6.7 %) and more equal between the ASD and control fathers (3.3 vs. 4.8 %). The ASD mothers scored significantly higher than control mothers on all SPAI scales. ASD fathers scored significantly higher than control fathers on the somatic, cognitive, avoidance and agoraphobic symptoms of SA. It is of clinical import to support ASD parents' well-being as their psychiatric features may contribute greatly to their children's emotional development and the well-being of the whole family.

Homeobox genes in obsessive-compulsive disorder

BACKGROUND

Despite evidence that obsessive-compulsive disorder (OCD) is a familial neuropsychiatric condition, progress aimed at identifying genetic determinants of the disorder has been slow. The OCD Collaborative Genetics Study (OCGS) has identified several OCD susceptibility loci through linkage analysis.

METHODS

In this study we investigate two regions on chromosomes 15q and 1q by first refining the linkage region using additional short tandem repeat polymorphic (STRP) markers. We then performed association analysis on single nucleotide polymorphisms (SNP) genotyped (markers placed every 2-4 kb) in the linkage regions in the OCGS sample of 376 rigorously phenotyped affected families.

RESULTS

Three SNPs are most strongly associated with OCD: rs11854486 (P = 0.00005 [0.046 after adjustment for multiple tests]; genetic relative risk (GRR) = 11.1 homozygous and 1.6 heterozygous) and rs4625687 [P = 0.00007 (after adjustment = 0.06); GRR = 2.4] on 15q; and rs4387163 (P = 0.0002 (after adjustment = 0.08); GRR = 1.97) on 1q. The first SNP is adjacent to NANOGP8, the second SNP is in MEIS2, and the third is 150 kb between PBX1 and LMX1A.

CONCLUSIONS

All the genes implicated by association signals are homeobox genes and are intimately involved in neurodevelopment. PBX1 and MEIS2 exert their effects by the formation of a heterodimeric complex, which is involved in development of the striatum, a brain region involved in the pathophysiology of OCD. NANOGP8 is a retrogene of NANOG, a homeobox transcription factor known to be involved in regulation of neuronal development. These findings need replication; but support the hypothesis that genes involved in striatal development are implicated in the pathogenesis of OCD.

Multi-informant reports of psychiatric symptoms among high-functioning adolescents with Asperger syndrome or autism

The aim of the study was to examine psychiatric symptoms in high-functioning adolescents with autism spectrum disorders reported by multiple informants. Forty-three 11- to 17-year-old adolescents with Asperger syndrome (AS) or high-functioning autism (HFA) and 217 typically developed adolescents completed the Youth Self-Report (YSR), while their parents completed the Child Behavior Checklist (CBCL). Teachers of adolescents with AS/HFA completed the Teacher Report Form (TRF). The informants reported significantly more psychiatric symptoms, especially withdrawn, anxious/depressed, social and attention problems, in adolescents with AS/HFA than in controls. In contrast to findings in the general population, the psychiatric problems of adolescents with AS/HFA are well acknowledged by multiple informants, including self-reports. However, anxiety and depressive symptoms were more commonly reported by adolescents with AS/HFA and their teachers than their parents, indicating that some emotional distress may be hidden from their parents.

Case series: Sensory intolerance as a primary symptom of pediatric OCD

INTRODUCTION

Marked intolerance or intrusive re-experiencing of ordinary sensory stimuli that in turn drive functionally impairing compulsive behaviors are occasionally seen in young children with OCD.

METHODS

We describe a number of children with DSM-IV OCD ascertained from a family genetic study of pediatric OCD, whose intolerance of ordinary sensory stimuli created significant subjective distress and time-consuming ritualistic behavior that was clinically impairing.

RESULTS

In each case, these sensory symptoms were the primary presenting symptoms and were experienced in the absence of intrusive thoughts, images, or ideas associated with "conventional" OCD symptoms.

CONCLUSIONS

These symptoms suggest abnormalities in sensory processing and integration in at least a subset of OCD patients. Recognition of these sensory symptoms and sensory-driven behaviors as part of the broad phenotypic variation in children with OCD could help clinicians more easily identify OCD patients and facilitate treatment.

Evidence for potential relationship between SLC1A1 and a putative genetic linkage region on chromosome 14q to obsessive-compulsive disorder with compulsive hoarding

Obsessive-compulsive disorder (OCD) is likely a disorder involving complex genetic transmission. This suggests that multiple genetic and environmental factors are involved in its etiology. This is complicated further by the probability of genetic heterogeneity for this phenotype. In this report, we describe a preliminary approach to deal with both complexities. SLC1A1, a glutamate transporter gene on chromosome 9p, was originally proposed to be related to OCD based on two linkage studies, and subsequently association of OCD to the gene has been replicated. Additionally, genetic linkage to a subtype of OCD, compulsive hoarding, has been reported on chromosome 14q. We hypothesized that both genomic regions contribute to OCD in some instances. Using the analytic program GENEFINDER we found that conditioning linkage on chromosome 14q to a marker adjacent to SLC1A1, reduced the size of the linkage region on chromosome 14q and provided evidence for interaction between the regions on chromosomes 9p and 14q.

Confirmation of dyslexia susceptibility loci on chromosomes 1p and 2p, but not 6p in a Dutch sib-pair collection

In this study, we attempted to confirm genetic linkage to developmental dyslexia and reading-related quantitative traits of loci that have been shown to be associated with dyslexia in previous studies. In our sample of 108 Dutch nuclear families, the categorical trait showed strongest linkage to 1p36 (NPL-LOD = 2.1). LOD scores for quantitative traits word-reading, non-word reading, and rapid naming peaked near the same location as the categorical trait, as well as on chromosome 2. Non-word repetition showed little phenotypic correlation with dyslexia or with the other quantitative traits, and this trait showed linkage peaks on 11p and 15q. No evidence for linkage to 6p22-23 was found for this set of families. Comparison of our results and literature data shows that loci link to different phenotypes in different samples. The mutual connections of these traits and their relation to developmental dyslexia remain elusive.

Further evidence for co-segregation between pediatric obsessive compulsive disorder and attention deficit hyperactivity disorder: a familial risk analysis

BACKGROUND

To examine the relationship between obsessive compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) in children and adolescents using familial risk analysis.

METHODS

We assessed for ADHD and OCD in the 1057 first-degree relatives of three groups of index children: those with OCD and ADHD, those with OCD but no ADHD and matched controls with neither disorder.

RESULTS

The age-corrected risk for OCD was similarly elevated in families of OCD youth with (14.8%) and without ADHD (17.5%) (p=.78), and both groups had significantly higher rates of OCD compared with controls (.5%) (p<.001). In contrast, the risk for ADHD was significantly elevated only among relatives of youth who had ADHD (15.3%) compared with controls (4.6%) (p<.001). Relatives affected with ADHD also had a significantly elevated risk for OCD compared to relatives unaffected by ADHD (20% vs. 4.9%, hazard ratio 4.8) (p<.001) and the two disorders occurred together with higher than expected frequency in affected relatives of OCD+ADHD probands (p<. 001) suggesting co-segregation between these two disorders. There was no evidence of nonrandom mating between OCD- and ADHD-affected spouses.

CONCLUSIONS

These results extend previous findings regarding the familiality of both OCD and ADHD and provide further evidence of a familial relationship between ADHD and pediatric OCD which best fit the hypothesis of a unique familial subtype.

Familiality of factor analysis-derived YBOCS dimensions in OCD-affected sibling pairs from the OCD Collaborative Genetics Study

BACKGROUND

Identification of familial, more homogenous characteristics of obsessive-compulsive disorder (OCD) may help to define relevant subtypes and increase the power of genetic and neurobiological studies of OCD. While factor-analytic studies have found consistent, clinically meaningful OCD symptom dimensions, there have been only limited attempts to evaluate the familiality and potential genetic basis of such dimensions.

METHODS

Four hundred eighteen sibling pairs with OCD were evaluated using the Structured Clinical Interview for DSM-IV and the Yale-Brown Obsessive Compulsive Scale (YBOCS) Symptom Checklist and Severity scales.

RESULTS

After controlling for sex, age, and age of onset, robust sib-sib intraclass correlations were found for two of the four YBOCS factors: Factor IV (hoarding obsessions and compulsions (p = .001) and Factor I (aggressive, sexual, and religious obsessions, and checking compulsions; p = .002). Smaller, but still significant, familiality was found for Factor III (contamination/cleaning; p = .02) and Factor II (symmetry/ordering/arranging; p = .04). Limiting the sample to female subjects more than doubled the familiality estimates for Factor II (p = .003). Among potentially relevant comorbid conditions for genetic studies, bipolar I/II and major depressive disorder were strongly associated with Factor I (p < .001), whereas ADHD, alcohol dependence, and bulimia were associated with Factor II (p < .01).

CONCLUSIONS

Factor-analyzed OCD symptom dimensions in sibling pairs with OCD are familial with some gender-dependence, exhibit relatively specific relationships to comorbid psychiatric disorders and thus may be useful as refined phenotypes for molecular genetic studies of OCD.

Examining the relationship between obsessive-compulsive disorder and attention-deficit/hyperactivity disorder in children and adolescents: a familial risk analysis

BACKGROUND

To use family study methodology to examine the relationship between obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD) in children and adolescents.

METHODS

We assessed for ADHD and OCD in the 1533 first-degree relatives of three groups of index children: those with ADHD and OCD, those with ADHD but no OCD, and matched controls with neither disorder.

RESULTS

The risk for ADHD was similarly elevated in families of ADHD youth with (18.9%) and without OCD (20.1%; p = .91), and both groups had significantly higher rates of ADHD compared with controls (4.6%; p < or = .001), which was consistent with previous research showing a strong familial risk for ADHD. The risk for OCD was significantly elevated only among relatives of youth with ADHD plus comorbid OCD (13.0%) compared with controls (.5%; p < or = .001) and was consistent with previous research showing a strong familial risk for OCD. Relatives affected with ADHD had a significantly elevated risk for OCD compared with relatives unaffected by ADHD (7.4% vs. 1.3%; p < .001), suggestive of co-segregation between these disorders. There was no evidence of nonrandom mating between ADHD- and OCD-affected spouses.

CONCLUSIONS

These results extend previously reported findings regarding the heritability of both ADHD and OCD and provide new evidence of a familial relationship between ADHD and pediatric OCD that best fits the hypothesis of a unique familial subtype.

Autism and the serotonin transporter: the long and short of it

Autism is a neurodevelopmental disorder manifesting early in childhood. Some symptoms of autism are alleviated by treatment with selective serotonin reuptake inhibitors, which are known to interact with the serotonin transporter. Moreover, variation in the gene that encodes the transporter (SLC6A4), especially the HTTLPR locus, is known to modulate its expression. It is natural, therefore, to evaluate whether this variation plays a role in liability to autism. We investigated the impact of alleles at HTTLPR and three other loci in SLC6A4 by using a large, independent family-based sample (390 families, 1528 individuals) from the NIH Collaborative Programs of Excellence in Autism (CPEA) network. Allele transmissions to individuals diagnosed with autism were biased only for HTTLPR, both for the narrow diagnosis of autism (P=0.035) and for the broader diagnosis of autism spectrum (P=0.007). The short allele of HTTLPR was significantly overtransmitted. Investigation of haplotype transmissions suggested that, in our data, biased transmission was only due to HTTLPR. With respect to this locus, there are now seven of 12 studies reporting significant transmission bias of HTTLPR alleles, a noteworthy result in itself. However, the studies with significant findings are almost equally divided between overtransmission of short and overtransmission of long alleles. We place our results within this extremely heterogeneous field of studies. Determining the factors influencing the relationship between autism phenotypes and HTTLPR variation, as well as other loci in SLC6A4, could be an important advance in our understanding of this complex disorder.

Early-onset obsessive-compulsive disorder: a subgroup with a specific clinical and familial pattern?

BACKGROUND

The familial nature of obsessive-compulsive disorder (OCD) has been previously demonstrated. The identification of candidate symptoms such as age at onset may help to disentangle the clinical and genetic heterogeneity of the disorder. In this study, the specificity of early-onset OCD was investigated, focusing on the effect of gender, comorbid conditions and familial risk of tics and OCD by studying a population consisting exclusively of patients with early-onset OCD.

METHODS

One hundred and forty-four patients having OCD were recruited in the study (108 early-onset probands and 36 late-onset probands). The early-onset probands and 199 of their first-degree relatives were investigated using structured interviews and questionnaires. This sample of early onset was mainly composed of children and adolescents (74 children and adolescents and 34 adults).

RESULTS

The average age of onset of OCD is 9.98+/-3.2 years. Forty-four per cent of the probands have a comorbid tic disorder. The age-corrected morbid risk among the first-degree relatives is 17% for OCD and 12% for tics. Morbid risk for OCD and tics was independent of the presence of tics in probands. Only 32.6% of the probands have a positive family history of OCD.

CONCLUSIONS

These findings are consistent with other reports in the literature that the morbid risk of OCD is elevated in relatives of probands with early-onset OCD. However, the majority of cases do not have a positive family history of OCD. This result suggests that early onset is not the only specific clinical marker for familial risk in OCD. Thus more work is needed to clearly elucidate other factors related to increased genetic vulnerability for OCD.

Three Diagnostic Approaches to Asperger Syndrome: Implications for Research

OBJECTIVE

To examine the implications for research of the use of three alternative definitions for Asperger syndrome (AS). Differences across the three nosologic systems were examined in terms of diagnostic assignment, IQ profiles, comorbid symptoms, and familial aggregation of social and other psychiatric symptoms.

METHOD

Standard data on diagnosis, intellectual functioning, comorbidity patterns, and family history were obtained on 65 individuals screened for a very high probability of having autism without mental retardation (or higher functioning autism, HFA) or AS. Diagnoses of AS were established based on three different approaches: DSM-IV, presence/absence of communicative phrase speech by 3 years, and a system designed to highlight prototypical features of AS.

RESULTS

Agreement between the three diagnostic systems was poor. AS could be differentiated from HFA (but not from PDD-NOS) on the basis of IQ profiles in two of the three systems. Differences in patterns of comorbid symptomatology were obtained in two of the three systems, although differences were primarily driven by the PDD-NOS category. Only one of the approaches yielded differences relative to aggregation of the "broader phenotype" in family members.

CONCLUSIONS

Diagnostic assignments of AS based on three commonly used approaches have low agreement and lead to different results in comparisons of IQ profiles, patterns of comorbidity, and familial aggregation of psychiatric symptoms across the approach-specific resultant groups of HFA, AS, and PDD-NOS.

Long-term outcome of pediatric obsessive-compulsive disorder: a meta-analysis and qualitative review of the literature

OBJECTIVE

To review the extant literature on the long-term outcome of child/adolescent-onset obsessive-compulsive disorder (OCD).

METHOD

Medline and Psychlit databases were systematically searched for articles regarding long-term outcomes of child/adolescent-onset OCD. Meta-analysis regression was applied to evaluate predictors and persistence of OCD.

RESULTS

Sixteen study samples (n = 6-132; total = 521 participants) in 22 studies had follow-up periods ranging between 1 and 15.6 years. Pooled mean persistence rates were 41% for full OCD and 60% for full or subthreshold OCD. Earlier age of OCD onset (z = -3.26, P = 0.001), increased OCD duration (z = 2.22, P = 0.027) and in-patient vs. out-patient status (z = 2.94, P = 0.003) predicted greater persistence. Comorbid psychiatric illness and poor initial treatment response were poor prognostic factors. Although psychosocial function was frequently compromised, most studies lacked comprehensive outcome measures.

CONCLUSION

Long-term persistence of pediatric OCD may be lower than believed. Future studies should include broader measures of outcome including symptomatic persistence and functional impairment in multiple domains.

Alleles of a reelin CGG repeat do not convey liability to autism in a sample from the CPEA network

A recent study by Persico et al. [2001: Mol Psychiatry 6:150-159] suggests alleles of a CGG polymorphism, just 5' of the reelin gene (RELN) initiator codon, confer liability for autism, especially alleles bearing 11 or more CGG repeats (long alleles). The association is consistent across both a case-control and family-based sample. We attempted to replicate their finding using a larger, independent family-based sample from the NIH Collaborative Programs of Excellence in Autism (CPEA) Network. In our data, allele transmissions to individuals with autism versus unaffected individuals are unbiased, both when alleles are classified by repeat length and when they are classified into long/short categories. Because of the apparent linkage of autism to chromosome 7q, particularly related to the development of language, we also evaluate the relationship between Reelin alleles and the age at which autism subjects use their first word or first phrase. Neither is significantly associated with Reelin alleles. Our results are not consistent with a major role for Reelin alleles in liability to autism.

The Military Life Scale: a measure of perceived stress and support in the Israeli Defense Force

GOALS

The purpose of this study was to construct a reliable and valid measure of perceived stress and support by adolescents in the Israeli military, and to explore its structure and psychometric properties.

METHOD

A large stratified sample of soldiers, representing different types of units, different lengths of service in the Israel Defense Force, and different ranks, were administered the Military Life Scale. Principal component factor analysis with varimax rotation resulted in a 5-factor structure for the stress scale, and a 5-factor structure for the support scale.

RESULTS

All factor-derived scales showed satisfactory scale reliability and discriminant validity.

CONCLUSIONS

The Military Life Scale is useful for measuring the stress experienced by individuals and groups within the Israel Defense Force. In addition, the Military Life Scale may be of use in other military environments, and with minor revision, in non-military environments in which the normative passage from late adolescence into adulthood occurs, such as a college setting.

Autism

Autism is a disorder characterised by severe difficulties in social interaction and communication, and with unusual behaviours. Once thought of as rare, autism is now recognised as being common. The role of CNS factors in pathogenesis is suggested by high rates of seizure disorder; research has highlighted the role of several specific brain regions in syndrome pathogenesis. Autism is a strongly genetic disorder and probably arises because of multiple genes; recurrence rates in families with one child are high. Early intervention with various techniques is helpful in many cases. Some pharmacological agents may help with certain problematic behaviours but do not address the underlying cause of the disorder.

Familial aggregation of delusional proneness in schizophrenia and bipolar pedigrees

OBJECTIVE

Clinical, familial, and, more recently, genetic linkage studies suggest that overlapping genetic susceptibility might contribute to both schizophrenia and bipolar disorder. To identify a potential psychotic dimension common to families of both bipolar and schizophrenia probands, the authors tested if delusional proneness was observed among first-degree relatives of bipolar and schizophrenia probands.

METHOD

The authors included 32 schizophrenia probands and 61 bipolar probands and their respective first-degree relatives (N=63 and N=59). They were all interviewed with the Diagnostic Interview for Genetic Studies, and delusional proneness was assessed with a self-report questionnaire, the Peters et al. Delusions Inventory. Schizophrenia and bipolar probands were subdivided into subgroups according to the intensity of delusional symptoms assessed by Peters et al. Delusions Inventory scores, and the authors compared delusional proneness in their respective first-degree relatives.

RESULTS

Familial aggregation of delusional proneness was demonstrated, since Peters et al. Delusions Inventory scores were higher among nonschizophrenic first-degree relatives of schizophrenia probands with productive symptoms and among first-degree relatives of bipolar probands with psychotic features during their affective episodes. The authors also found an intrafamilial correlation of delusional proneness scores in nonaffected siblings of schizophrenia and bipolar probands.

CONCLUSIONS

Delusional proneness appears to be an inherited predisposition common to both schizophrenia and bipolar disorder. In the future, this dimension might be valuable when used as a quantitative phenotype in linkage and association studies.

Continuing the search for dyslexia genes on 6p

This study is a continuation and extension of the work with Orton Developmental Dyslexia (DD) pedigrees [Grigorenko et al., 1997; 2000, Grigorenko et al., 2001]. This study utilized an extended sample (N = 176) and a well-saturated map of chromosome 6p (30 markers). Six phenotypes were constructed to span a range of dyslexia-related cognitive processes. These phenotypes were: (1) Phonemic Awareness (of spoken words); (2) Phonological Decoding (of printed nonwords); (3) Rapid Automatized Naming (of colored squares or object drawings); (4) Single Word Reading (orally, of printed real words); (5) Phonemic Awareness/Decoding/Single-Word Reading pathway; and (6) Phonemic Awareness/Rapid Naming/Single-Word Reading pathway. The study resulted in two major findings. First, considering the distributions of the genetic linkage indicators across all phenotypes examined, there appear to be three regions of interest (around markers D6S109, D6S1261, and in the D6S105-D6S265 region). Any of these regions could serve as a starting point in the search for specific gene candidates contributing to the manifestation of DD, yet they all might be echo peaks of a single peak, the boundary of which is difficult to establish due to the limited power of this sample. Second, the DD-related linkage in 6p21.3 appears to be most closely related to the manifestations of DD through phonemic awareness and single-word reading deficits.

No evidence for linkage of liability to autism to HOXA1 in a sample from the CPEA network

A recent study by Ingram et al. [2000b: Teratology 62:393-405] suggests a (His)73(Arg) polymorphism (A:G) in HOXA1 contributes substantially to a liability for autism. Using 68 individuals diagnosed with Autism Spectrum Disorders, they found a significant dearth of G homozygotes and biased transmission of G alleles from parents to affected offspring, especially from mothers. Because the connection between HOXA1 and liability to autism is compelling, we attempted to replicate their finding using a larger, independent sample from the Collaborative Programs of Excellence in Autism (CPEA) network. In our data, genotype frequencies conform to Hardy-Weinberg equilibrium; allele transmissions meet Mendelian expectations; and there is no obvious sex-biased allele transmission. Based on our sample size, calculations suggest that we would have at least 95% power to detect linkage and association even if the A:G polymorphism were to account for only 1% of the heritability of autism. Therefore, although we cannot exclude the possibility that the samples in the two studies are intrinsically different, our data from our sample argue against a major role for HOXA1 (His)73(Arg) in liability to autism.

Evidence for linkage and association with reading disability on 6p21.3-22

Reading disability (RD), or dyslexia, is a common heterogeneous syndrome with a large genetic component. Several studies have consistently found evidence for a quantitative-trait locus (QTL) within the 17 Mb (14.9 cM) that span D6S109 and D6S291 on chromosome 6p21.3-22. To characterize further linkage to the QTL, to define more accurately the location and the effect size, and to identify a peak of association, we performed Haseman-Elston and DeFries-Fulker linkage analyses, as well as transmission/disequilibrium, total-association, and variance-components analyses, on 11 quantitative reading and language phenotypes. One hundred four families with RD were genotyped with a new panel of 29 markers that spans 9 Mb of this region. Linkage results varied widely in degree of statistical significance for the different linkage tests, but multipoint analysis suggested a peak near D6S461. The average 6p QTL heritability for the 11 reading and language phenotypes was 0.27, with a maximum of 0.66 for orthographic choice. Consistent with the region of linkage described by these studies and others, there was a peak of transmission disequilibrium with a QTL centered at JA04 (chi2=9.48; empirical P=.0033; orthographic choice), and there was strong evidence for total association at this same marker (chi2=11.49; P=.0007; orthographic choice). Although the boundaries of the peak could not be precisely defined, the most likely location of the QTL is within a 4-Mb region surrounding JA04.

Human GABA(B) receptor 1 gene: eight novel sequence variants

GABA (gamma-aminobutyric acid) is the principal inhibitory neurotransmitter in the brain. The human GABA(B) receptor (GABBR1) maps to the human leukocyte antigen (HLA) region of chromosome 6. Its function and location in a susceptibility region for schizophrenia, epilepsy, and dyslexia make GABBR1 a candidate gene for neurobehavioral disorders. We report the characterization of GABBR1 gene mutations in 100 chromosomes from a mixed American population. Eleven distinct mutations were found, including two previously reported missense mutations (A20V and G489S) and a previously reported silent 1977 T>C transition. Here, we report four novel silent substitutions (39C>T, 1473T>C, 1476T>C, 1545T>C) and four novel intron variants. These DNA variants may be useful in association and linkage studies of neurobehavioral disorders, and in pharmacogenetic studies of drugs targeting GABBR1.

Stereotactic breast biopsy: recumbent biopsy using add-on upright equipment

OBJECTIVE

The purpose of the study was to show that stereotactic breast biopsy can be performed effectively and accurately using add-on stereotactic equipment when it is performed with the patient in a decubitus or recumbent position.

MATERIALS AND METHODS

We retrospectively reviewed the results of 225 stereotactic core breast biopsies performed during a 42-month period. The biopsies were performed using a reclining mammography chair and add-on stereotactic equipment. Procedures were performed with the patient in the right or left lateral decubitus position or upright. Patients with benign biopsy results were followed up mammographically at 6 months initially, then yearly.

RESULTS

Of the 225 lesions biopsied stereotactically, 205 lesions (91%) were biopsied with the patient in the decubitus (right or left) position and 20 (9%) biopsied with the patient upright. Pathology results were classified as abnormal in 45 lesions (20%) and normal in 180 lesions (80%). All but one of the abnormal lesions were followed up with surgical excision. One hundred thirty-four of the 180 benign lesions have been followed up with at least one 6-month mammogram (follow-up range, 6-40 months), and none of the lesions has been subsequently proven malignant.

CONCLUSION

Stereotactic core biopsy can be performed effectively and accurately using standard add-on equipment when it is performed with the patient in the decubitus position. This approach obviates the use of dedicated prone stereotactic equipment.

Genome scan for linkage to Gilles de la Tourette syndrome

Gilles de la Tourette Syndrome (TS) is a neuropsychiatric disorder characterized by both motor and vocal tics. Despite clear evidence for a genetic predisposition to TS from family, twin, and adoption studies, there have been no confirmed linkage findings. In this article we test for linkage to TS in multigenerational families segregating TS using a panel of 386 markers with the largest interval between any two markers being 28 cM and an average distance between markers of 10 cM. We tested for linkage using an autosomal dominant model with reduced penetrance and using nonparametric methods. No significant evidence for linkage was found with parametric analysis. A logarithm of the odds (LOD) score of greater or equal to one under the autosomal dominant model was observed in 24 of these markers in at least one of the families tested. No LOD scores greater than two were observed with any of the markers. For the nonparametric analysis, eight markers were observed with a P-value less than 0.00005 for significance evidence of linkage in at least one family. However caution should be used in the interpretation of the nonparametric analyses as this statistic (the affected-pedigree-member method) is know to have a high false-positive rate. Further support for linkage in these regions is required before linkage can be assumed.

Nosological and genetic aspects of Asperger syndrome

The validity of Asperger syndrome (i.e., apart from high-functioning autism) continues to be the topic of considerable debate. Consistent with Asperger's original description of the condition there appear to be some important potential differences from autism if both conditions are strictly defined. Although the importance of genetic factors in the transmission of autism is increasingly clear it also appears that genetic factors may play an even more important role in Asperger syndrome (AS). The nosological validity of this condition and its relation to the various PDD spectrum disorder remains an important topic for future research. Well-designed and carefully controlled studies are needed in which patterns of comorbidity and associated problems in family members can be carefully assessed. Such studies will contribute to our understanding of the relationship of AS and autism and may clarify important genetic mechanisms of relevance to autism.

Visual-motor integration functioning in children with Tourette syndrome

A neuropsychological model of visual-motor integration skill was proposed and tested in 50 children with Tourette syndrome (TS) and 23 unaffected control children matched for age. Children with TS performed significantly worse than control children on the Beery Visual-Motor Integration (VMI) Test. Consistent with the proposed model, visuoperceptual and fine-motor coordination subprocesses were significant predictors of VMI scores. However, the subprocesses did not fully account for the diagnostic group difference on the VMI. These results suggest that the integration of visual inputs and organized motor output is a specific area of neuropsychological weakness among individuals with TS.

Psychiatric genetics: search for phenotypes

Failure to obtain convincing results in psychiatric genetics can partly be attributed to the fact that progress in molecular biology and genetic epidemiology has not been followed by an equivalent development in phenotypic description. Instead of relying entirely on classical nosological approaches, we argue that identifying more homogeneous forms of diseases through a'candidate symptom approach' among affected subjects and an endophenotype approach that identifies sub-clinical traits among non-affected relatives might yield better results. Examples where these strategies have already been fruitful when applied to complex diseases are presented in this review. Focusing on vulnerability traits might stimulate the redefinition of traditional psychiatric syndromes and help to bridge the gap between clinical and experimental approaches.

Visual-motor integration functioning in children with Tourette syndrome

A neuropsychological model of visual-motor integration skill was proposed and tested in 50 children with Tourette syndrome (TS) and 23 unaffected control children matched for age. Children with TS performed significantly worse than control children on the Beery Visual-Motor Integration (VMI) Test. Consistent with the proposed model, visuoperceptual and fine-motor coordination subprocesses were significant predictors of VMI scores. However, the subprocesses did not fully account for the diagnostic group difference on the VMI. These results suggest that the integration of visual inputs and organized motor output is a specific area of neuropsychological weakness among individuals with TS.

Neuropsychiatric disorders of childhood: Tourette's syndrome as a model

Neuropsychiatric disorders of childhood include conditions such as autism, pervasive developmental disorder and attention deficit hyperactivity disorder. Tourette's syndrome (TS) of chronic, multiple, motor and vocal tics is a model neuropsychiatric disorder with a childhood onset and long-term, and sometimes life-long, course. Symptoms and signs change during the course of maturation, and include obsessions, compulsions, attentional difficulties and psychological responses to the disability. These clinical features reflect the interaction between genetic and environmental factors. The localization and cloning of the genetic substrate will allow for detailed study of the pathways from molecular vulnerability to clinical syndrome.

Ritual, habit, and perfectionism: the prevalence and development of compulsive-like behavior in normal young children

Young children engage in a significant amount of ritualistic, repetitive, and compulsive-like activity that appears to be part of their normal behavioral repertoire. Empirically, little is known about the onset, prevalence, and developmental trajectory of these phenomena. A parent-report questionnaire, the Childhood Routines Inventory (CRI), was developed to assess compulsive-like behavior in young children, and was administered to 1,492 parents with children between the ages of 8 and 72 months. The CRI has strong overall internal consistency and a distinct two-factor structure. The frequency of compulsive-like behaviors changes with age: Two-, 3-, and 4-year-olds engaged in more compulsive behavior than children younger than 1 year of age and older than 4 years of age. Results are discussed from a developmental psychopathology framework and for their implications for future research in this area.

Elevated cerebrospinal fluid corticotropin-releasing factor in Tourette's syndrome: comparison to obsessive compulsive disorder and normal controls

Stress- and anxiety-related fluctuations in tic severity are cardinal features of Tourette's syndrome (TS), and there is evidence for involvement of noradrenergic mechanisms in the pathophysiology and treatment of the disorder. To examine further the pathobiology of this enhanced vulnerability to stress and anxiety, we measured central activity of corticotropin-releasing factor (CRF) in patients with TS and the related condition, obsessive compulsive disorder (OCD). Lumbar cerebrospinal fluid (CSF) was obtained in a standardized fashion for measurement of CRF from 21 medication-free outpatients with TS, 20 with OCD, and 29 healthy controls. The TS patients had significantly higher levels of CSF CRF than both the normal controls and the OCD patients. However, there was no difference in CSF CRF between the OCD patients and the normal controls. Group differences in CSF CRF were unrelated to current clinical ratings of depression, anxiety, tics, and obsessive compulsive behaviors. Although the functional significance of this finding remains to be elucidated, these results are consistent with the hypothesis that stress-related neurobiological mechanisms may play a role in the pathobiology of TS.

Psychiatric disorders in relatives of probands with opiate addiction

Previous research has documented high rates of major depression and antisocial personality in opiate addicts. This study was designed to investigate the relationship of dual diagnosis in opiate-addicted probands to family history of psychiatric disorders and substance use disorders in biological relatives. Psychiatric disorders and substance use disorders were evaluated using direct interview and family history in a sample of 877 first-degree relatives of 201 opiate addicts and 360 relatives of 82 normal controls. Results indicate that (1) compared with relatives of normal subjects, opiate addicts' relatives had substantially higher rates of alcoholism, drug abuse, depression, and antisocial personality; (2) relatives of depressed opiate-addicted probands had elevated rates of major depression and anxiety disorders but not of other disorders, suggesting the validity of subtyping opiate addicts by the presence or absence of major depression; and (3) in contrast, relatives of antisocial opiate addicts had rates of disorders that were not significantly different from those of relatives of opiate addicts without antisocial personality. Implications of these findings for the classification and treatment of substance abuse are discussed.

Aneuploidy and the fragile X syndrome

The possibility that female carriers of the fragile X gene(s) are at increased risk for nondisjunctional events leading to aneuploid offspring has been suggested by several investigators. To better address this question we analyzed pedigrees of 117 families in which the fragile X syndrome is segregating. The 117 pedigrees, originally collected for segregation analyses, included 236 females with offspring whose carrier status was determined by cytogenetic or pedigree analysis or by analyses using flanking DNA markers. These 236 females have had 931 offspring including one 47,XXY and 6 trisomy 21 individuals (1/155). Statistical analysis suggested that the observed rate of trisomy 21 was significantly higher than expected (Fisher's exact test, p less than or equal to 0.05). Assuming a Poisson distribution to calculate the confidence interval for the observed rate of trisomy 21 individuals, we found that the expected rate of 1.6/1000 in this sample fell outside the 99% confidence limits of our observed rate of 1/155. Additional data from a larger sample are needed to replicate these findings.

Severity of Tourette's syndrome in one large kindred. Implication for determination of disease prevalence rate

An accurate prevalence rate for Tourette's syndrome (TS) has not been established. To assess severity of illness, a potential source of bias in determining prevalence rate, we administered standardized questionnaires and examinations to 159 members of a large Mennonite kindred showing apparent autosomal dominant transmission of motor and vocal tics (TS) or chronic motor tics (CMTs). Fifty-four family members were diagnosed as having definite or probable TS or CMTs. For these 54 subjects, 30% (n = 16) were unaware of tics noted by the examiners and only 18.5% (n = 10) had sought medical care. Our findings suggest that most cases of TS and CMTs are mild and do not come to medical attention. These tic disorders are probably much more prevalent than generally appreciated.

Familial Tourette's syndrome: report of a large pedigree and potential for linkage analysis

We studied a large Mennonite kindred affected by chronic motor tics (CMTs) and vocal tics in a probable autosomal dominant pattern. We administered a standardized questionnaire to 69 family members and reviewed our videotapes of 47. Using DSM III criteria and independent ratings, we diagnosed 10 subjects as having definite Tourette's syndrome (TS), 3 with definite CMTs, 15 with probable TS, and 1 with probable CMT. The clinical features of this family are presented. This is the largest known kindred with TS. Permanent lymphoblastoid cell lines have been established from 67 family members for genetic linkage analysis.