Assessing the effects of therapeutic combinations on SARS-CoV-2 infected patient outcomes: A big data approach

BACKGROUND

The COVID-19 pandemic has demonstrated the need for efficient and comprehensive, simultaneous assessment of multiple combined novel therapies for viral infection across the range of illness severity. Randomized Controlled Trials (RCT) are the gold standard by which efficacy of therapeutic agents is demonstrated. However, they rarely are designed to assess treatment combinations across all relevant subgroups. A big data approach to analyzing real-world impacts of therapies may confirm or supplement RCT evidence to further assess effectiveness of therapeutic options for rapidly evolving diseases such as COVID-19.

METHODS

Gradient Boosted Decision Tree, Deep and Convolutional Neural Network classifiers were implemented and trained on the National COVID Cohort Collaborative (N3C) data repository to predict the patients' outcome of death or discharge. Models leveraged the patients' characteristics, the severity of COVID-19 at diagnosis, and the calculated proportion of days on different treatment combinations after diagnosis as features to predict the outcome. Then, the most accurate model is utilized by eXplainable Artificial Intelligence (XAI) algorithms to provide insights about the learned treatment combination impacts on the model's final outcome prediction.

RESULTS

Gradient Boosted Decision Tree classifiers present the highest prediction accuracy in identifying patient outcomes with area under the receiver operator characteristic curve of 0.90 and accuracy of 0.81 for the outcomes of death or sufficient improvement to be discharged. The resulting model predicts the treatment combinations of anticoagulants and steroids are associated with the highest probability of improvement, followed by combined anticoagulants and targeted antivirals. In contrast, monotherapies of single drugs, including use of anticoagulants without steroid or antivirals are associated with poorer outcomes.

CONCLUSIONS

This machine learning model by accurately predicting the mortality provides insights about the treatment combinations associated with clinical improvement in COVID-19 patients. Analysis of the model's components suggests benefit to treatment with combination of steroids, antivirals, and anticoagulant medication. The approach also provides a framework for simultaneously evaluating multiple real-world therapeutic combinations in future research studies.

Increased resting-state thalamocortical functional connectivity in children and young adults with autism spectrum disorder

There is converging evidence that abnormal thalamocortical interactions contribute to attention deficits and sensory sensitivities in autism spectrum disorder (ASD). However, previous functional MRI studies of thalamocortical connectivity in ASD have produced inconsistent findings in terms of both the direction (hyper vs. hypoconnectivity) and location of group differences. This may reflect, in part, the confounding effects of head motion during scans. In the present study, we investigated resting-state thalamocortical functional connectivity in 8-25 year-olds with ASD and their typically developing (TD) peers. We used pre-scan training, on-line motion correction, and rigorous data quality assurance protocols to minimize motion confounds. ASD participants showed increased thalamic connectivity with temporal cortex relative to TD. Both groups showed similar age-related decreases in thalamic connectivity with occipital cortex, consistent with a process of circuit refinement. Findings of thalamocortical hyperconnectivity in ASD are consistent with other evidence that decreased thalamic inhibition leads to increase and less filtered sensory information reaching the cortex where it disrupts attention and contributes to sensory sensitivity. This literature motivates studies of mechanisms, functional consequences, and treatment of thalamocortical circuit dysfunction in ASD.

Community risks for SARS-CoV-2 infection among fully vaccinated US adults by rurality: A retrospective cohort study from the National COVID Cohort Collaborative

BACKGROUND

While COVID-19 vaccines reduce adverse outcomes, post-vaccination SARS-CoV-2 infection remains problematic. We sought to identify community factors impacting risk for breakthrough infections (BTI) among fully vaccinated persons by rurality.

METHODS

We conducted a retrospective cohort study of US adults sampled between January 1 and December 20, 2021, from the National COVID Cohort Collaborative (N3C). Using Kaplan-Meier and Cox-Proportional Hazards models adjusted for demographic differences and comorbid conditions, we assessed impact of rurality, county vaccine hesitancy, and county vaccination rates on risk of BTI over 180 days following two mRNA COVID-19 vaccinations between January 1 and September 21, 2021. Additionally, Cox Proportional Hazards models assessed the risk of infection among adults without documented vaccinations. We secondarily assessed the odds of hospitalization and adverse COVID-19 events based on vaccination status using multivariable logistic regression during the study period.

RESULTS

Our study population included 566,128 vaccinated and 1,724,546 adults without documented vaccination. Among vaccinated persons, rurality was associated with an increased risk of BTI (adjusted hazard ratio [aHR] 1.53, 95% confidence interval [CI] 1.42-1.64, for urban-adjacent rural and 1.65, 1.42-1.91, for nonurban-adjacent rural) compared to urban dwellers. Compared to low vaccine-hesitant counties, higher risks of BTI were associated with medium (1.07, 1.02-1.12) and high (1.33, 1.23-1.43) vaccine-hesitant counties. Compared to counties with high vaccination rates, a higher risk of BTI was associated with dwelling in counties with low vaccination rates (1.34, 1.27-1.43) but not medium vaccination rates (1.00, 0.95-1.07). Community factors were also associated with higher odds of SARS-CoV-2 infection among persons without a documented vaccination. Vaccinated persons with SARS-CoV-2 infection during the study period had significantly lower odds of hospitalization and adverse events across all geographic areas and community exposures.

CONCLUSIONS

Our findings suggest that community factors are associated with an increased risk of BTI, particularly in rural areas and counties with high vaccine hesitancy. Communities, such as those in rural and disproportionately vaccine hesitant areas, and certain groups at high risk for adverse breakthrough events, including immunosuppressed/compromised persons, should continue to receive public health focus, targeted interventions, and consistent guidance to help manage community spread as vaccination protection wanes.

Higher hospitalization and mortality rates among SARS-CoV-2-infected persons in rural America

PURPOSE

Rural communities are among the most underserved and resource-scarce populations in the United States. However, there are limited data on COVID-19 outcomes in rural America. This study aims to compare hospitalization rates and inpatient mortality among SARS-CoV-2-infected persons stratified by residential rurality.

METHODS

This retrospective cohort study from the National COVID Cohort Collaborative (N3C) assesses 1,033,229 patients from 44 US hospital systems diagnosed with SARS-CoV-2 infection between January 2020 and June 2021. Primary outcomes were hospitalization and all-cause inpatient mortality. Secondary outcomes were utilization of supplemental oxygen, invasive mechanical ventilation, vasopressor support, extracorporeal membrane oxygenation, and incidence of major adverse cardiovascular events or hospital readmission. The analytic approach estimates 90-day survival in hospitalized patients and associations between rurality, hospitalization, and inpatient adverse events while controlling for major risk factors using Kaplan-Meier survival estimates and mixed-effects logistic regression.

FINDINGS

Of 1,033,229 diagnosed COVID-19 patients included, 186,882 required hospitalization. After adjusting for demographic differences and comorbidities, urban-adjacent and nonurban-adjacent rural dwellers with COVID-19 were more likely to be hospitalized (adjusted odds ratio [aOR] 1.18, 95% confidence interval [CI], 1.16-1.21 and aOR 1.29, CI 1.24-1.1.34) and to die or be transferred to hospice (aOR 1.36, CI 1.29-1.43 and 1.37, CI 1.26-1.50), respectively. All secondary outcomes were more likely among rural patients.

CONCLUSIONS

Hospitalization, inpatient mortality, and other adverse outcomes are higher among rural persons with COVID-19, even after adjusting for demographic differences and comorbidities. Further research is needed to understand the factors that drive health disparities in rural populations.

An ordinal severity scale for COVID-19 retrospective studies using Electronic Health Record data

Objectives

Although the World Health Organization (WHO) Clinical Progression Scale for COVID-19 is useful in prospective clinical trials, it cannot be effectively used with retrospective Electronic Health Record (EHR) datasets. Modifying the existing WHO Clinical Progression Scale, we developed an ordinal severity scale (OS) and assessed its usefulness in the analyses of COVID-19 patient outcomes using retrospective EHR data.

Materials and Methods

An OS was developed to assign COVID-19 disease severity using the Observational Medical Outcomes Partnership common data model within the National COVID Cohort Collaborative (N3C) data enclave. We then evaluated usefulness of the developed OS using heterogenous EHR data from January 2020 to October 2021 submitted to N3C by 63 healthcare organizations across the United States. Principal component analysis (PCA) was employed to characterize changes in disease severity among patients during the 28-day period following COVID-19 diagnosis.

Results

The data set used in this analysis consists of 2 880 456 patients. PCA of the day-to-day variation in OS levels over the totality of the 28-day period revealed contrasting patterns of variation in disease severity within the first and second 14 days and illustrated the importance of evaluation over the full 28-day period.

Discussion

An OS with well-defined, robust features, based on discrete EHR data elements, is useful for assessments of COVID-19 patient outcomes, providing insights on the progression of COVID-19 disease severity over time.

Conclusions

The OS provides a framework that can facilitate better understanding of the course of acute COVID-19, informing clinical decision-making and resource allocation.

Heterozygous De Novo Truncating Mutation of Nucleolin in an ASD Individual Disrupts Its Nucleolar Localization

Nucleolin (NCL/C23; OMIM: 164035) is a major nucleolar protein that plays a critical role in multiple processes, including ribosome assembly and maturation, chromatin decondensation, and pre-rRNA transcription. Due to its diverse functions, nucleolin has frequently been implicated in pathological processes, including cancer and viral infection. We recently identified a de novo frameshifting indel mutation of NCL, p.Gly664Glufs*70, through whole-exome sequencing of autism spectrum disorder trios. Through the transfection of constructs encoding either a wild-type human nucleolin or a mutant nucleolin with the same C-terminal sequence predicted for the autism proband, and by using co-localization with the nucleophosmin (NPM; B23) protein, we have shown that the nucleolin mutation leads to mislocalization of the NCL protein from the nucleolus to the nucleoplasm. Moreover, a construct with a nonsense mutation at the same residue, p.Gly664*, shows a very similar effect on the location of the NCL protein, thus confirming the presence of a predicted nucleolar location signal in this region of the NCL protein. Real-time fluorescence recovery experiments show significant changes in the kinetics and mobility of mutant NCL protein in the nucleoplasm of HEK293Tcells. Several other studies also report de novoNCL mutations in ASD or neurodevelopmental disorders. The altered mislocalization and dynamics of mutant NCL (p.G664Glufs*70/p.G664*) may have relevance to the etiopathlogy of NCL-related ASD and other neurodevelopmental phenotypes.

447. An Ordinal Scale Assessing SARS-CoV-2 Infected Patient Outcomes Using Electronic Health Records

Background

A major challenge to identifying effective treatments for COVID-19 has been the conflicting results offered by small, often underpowered clinical trials. The World Health Organization (WHO) Ordinal Scale (OS) has been used to measure clinical improvement among clinical trial participants and has the benefit of measuring effect across the spectrum of clinical illness. We modified the WHO OS to enable assessment of COVID-19 patient outcomes using electronic health record (EHR) data.

Methods

Employing the National COVID Cohort Collaborative (N3C) database of EHR data from 50 sites in the United States, we assessed patient outcomes, April 1,2020 to March 31, 2021, among those with a SARS-CoV-2 diagnosis, using the following modification of the WHO OS: 1=Outpatient, 3=Hospitalized, 5=Required Oxygen (any), 7=Mechanical Ventilation, 9=Organ Support (pressors; ECMO), 11=Death. OS is defined over 4 weeks beginning at first diagnosis and recalculated each week using the patient’s maximum OS value in the corresponding 7-day period. Modified OS distributions were compared across time using a Pearson Chi-Squared test.

Results

The study sample included 1,446,831 patients, 54.7% women, 14.7% Black, 14.6% Hispanic/Latinx. Pearson Chi-Sq P< 0.0001 was obtained comparing the distribution of 2^nd Quarter 2020 OS with the distribution of later time points for Week 4.

Table 1. OS at week 1 and 4 by quarter

The study sample included 1,446,831 patients, 54.7% women, 14.7% Black, 14.6% Hispanic/Latinx. Pearson Chi-Sq P< 0.0001 was obtained comparing the distribution of 2nd Quarter 2020 OS with the distribution of later time points for Week 4.

Conclusion

All Week 4 OS distributions significantly improved from the initial period (April-June 2020) compared with subsequent months, suggesting improved management. Further work is needed to determine which elements of care are driving the improved outcomes. Time series analyses must be included when assessing impact of therapeutic modalities across the COVID pandemic time frame.

Disclosures

Sally L. Hodder, M.D., Gilead (Advisor or Review Panel member)Merck (Grant/Research Support, Advisor or Review Panel member)Viiv Healthcare (Grant/Research Support, Advisor or Review Panel member)

Association Between Earthquake Exposures and Mental Health Outcomes in Phulpingdanda Village After the 2015 Nepal Earthquakes

In 2015, two strong earthquakes, as well as continuous, high magnitude aftershocks, struck Nepal. Phulpingdanda village was greatly impacted due to its lack of infrastructure and environmental remoteness. Adults from sampled households were surveyed 1-year later to examine the association between earthquake exposures and indicators of depression, post-traumatic stress disorder (PTSD), and resilience. Results showed 33% of surveyed residents screened positive for depression, 9% screened positive for severe PTSD, and 46% displayed moderate to high resilience. Additionally, participants experienced resource loss (100%), damaged home and goods (99%), and exposure to the grotesque (82%). Traumatic earthquake experiences related to personal harm were associated with symptoms of depression and PTSD and resource loss was associated with depressive symptoms. Earthquake experiences associated with less damage to home and goods, but greater exposure to the grotesque were associated with increased resilience. This research adds to our knowledge of the relationship between traumatic exposures and indicators of psychological distress and resilience following a disaster.

Earthquake exposures and mental health outcomes in children and adolescents from Phulpingdanda village, Nepal: a cross-sectional study

BACKGROUND

Mental health issues can reach epidemic proportions in developed countries after natural disasters, but research is needed to better understand the impact on children and adolescents in developing nations.

METHODS

A cross-sectional study was performed to examine the relationship between earthquake exposures and depression, PTSD, and resilience among children and adolescents in Phulpingdanda village in Nepal, 1 year after the 2015 earthquakes, using the Depression Self-Rating Scale for Children, Child PTSD Symptom Scale, and the Child and Youth Resilience Measure, respectively. To quantify exposure, a basic demographic and household questionnaire, including an earthquake exposure assessment tool for children and adolescents, was created.

RESULTS

Of the 62 respondents interviewed, 3.23% and 4.84% displayed symptomatology of depression and PTSD. A large number of respondents interviewed scored high for resiliency (80.65%). All 62 respondents were displaced from their household and witnessed severe damage of both their homes and village. The number of earthquake exposures had a strong, positive correlation with PTSD symptomatology.

CONCLUSIONS

Although the number of respondents who showed signs of depression and PTSD symptomatology was lower than anticipated, resilience scores were considerably higher. Future research should explore which protective factors may contribute to high resiliency in Nepali children and adolescents.

Diffusion-weighted imaging evidence of altered white matter development from late childhood to early adulthood in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is thought to reflect disrupted development of brain connectivity characterized by white matter abnormalities and dyscoordination of activity across brain regions that give rise to core features. But there is little consensus about the nature, timing and location of white matter abnormalities as quantified with diffusion-weighted MRI. Inconsistent findings likely reflect small sample sizes, motion confounds and sample heterogeneity, particularly different age ranges across studies. We examined the microstructural integrity of major white matter tracts in relation to age in 38 high functioning ASD and 35 typically developing (TD) participants, aged 8-25, whose diffusion-weighted scans met strict data-quality criteria and survived group matching for motion. While there were no overall group differences in diffusion measures, the groups showed different relations with age. Only the TD group showed the expected positive correlations of fractional anisotropy with age. In parallel, axial diffusivity was unrelated to age in TD, but showed inverse correlations with age in ASD. Younger participants with ASD tended to have higher fractional anisotropy and axial diffusivity than their TD peers, while the opposite was true for older participants. Most of the affected tracts - cingulum bundle, inferior and superior longitudinal fasciculi - are association bundles related to cognitive, social and emotional functions that are abnormal in ASD. The manifestations of abnormal white matter development in ASD as measured by diffusion-weighted MRI depend on age and this may contribute to inconsistent findings across studies. We conclude that ASD is characterized by altered white matter development from childhood to early adulthood that may underlie abnormal brain function and contribute to core features.

Behavioral Outcomes of Specialized Psychiatric Hospitalization in the Autism Inpatient Collection (AIC): A Multisite Comparison

Psychiatric hospitalization of children with autism spectrum disorder (ASD) is relatively common and occurs at a higher rate than in non-ASD youth. This study compared changes in the severity of serious problem behaviors in 350 youth with ASD enrolled in the autism inpatient collection during and after hospitalization in six specialized child psychiatry units. There was a significant reduction in serious problem behaviors from admission (aberrant behavior checklist-irritability subscale M = 29.7, SD 9.6) to discharge (M = 15.0, SD 10.3) and 2-month follow-up (M = 19.3, SD 10.3). Between discharge and 2-month follow-up, tantrum-like behaviors but not self-injurious behaviors increased slightly. Improvement in the severity of problem behaviors was not uniform across sites, even after controlling for measured site differences.

The autism inpatient collection: methods and preliminary sample description

Background

Individuals severely affected by autism spectrum disorder (ASD), including those with intellectual disability, expressive language impairment, and/or self-injurious behavior (SIB), are underrepresented in the ASD literature and extant collections of phenotypic and biological data. An understanding of ASD’s etiology and subtypes can only be as complete as the studied samples are representative.

Methods

The Autism Inpatient Collection (AIC) is a multi-site study enrolling children and adolescents with ASD aged 4–20 years admitted to six specialized inpatient psychiatry units. Enrollment began March, 2014, and continues at a rate of over 400 children annually. Measures characterizing adaptive and cognitive functioning, communication, externalizing behaviors, emotion regulation, psychiatric co-morbidity, self-injurious behavior, parent stress, and parent self-efficacy are collected. ASD diagnosis is confirmed by the Autism Diagnostic Observation Schedule – 2 (ADOS-2) and extensive inpatient observation. Biological samples from probands and their biological parents are banked and processed for DNA extraction and creation of lymphoblastoid cell lines.

Results

Sixty-one percent of eligible subjects were enrolled. The first 147 subjects were an average of 12.6 years old (SD 3.42, range 4–20); 26.5 % female; 74.8 % Caucasian, and 81.6 % non-Hispanic/non-Latino. Mean non-verbal intelligence quotient IQ = 70.9 (SD 29.16, range 30–137) and mean adaptive behavior composite score = 55.6 (SD 12.9, range 27–96). A majority of subjects (52.4 %) were non- or minimally verbal. The average Aberrant Behavior Checklist - Irritability Subscale score was 28.6, well above the typical threshold for clinically concerning externalizing behaviors, and 26.5 % of the sample engaged in SIB. Females had more frequent and severe SIB than males.

Conclusions

Preliminary data indicate that the AIC has a rich representation of the portion of the autism spectrum that is understudied and underrepresented in extant data collections. More than half of the sample is non- or minimally verbal, over 40 % have intellectual disability, and over one quarter exhibit SIB. The AIC is a substantial new resource for study of the full autism spectrum, which will augment existing data on higher-functioning cohorts and facilitate the identification of genetic subtypes and novel treatment targets. The AIC investigators welcome collaborations with other investigators, and access to the AIC phenotypic data and biosamples may be requested through the Simons Foundation (www.sfari.org).

Parental social responsiveness and risk of autism spectrum disorder in offspring

IMPORTANCE

Although autism spectrum disorder (ASD) is known to be heritable, patterns of inheritance of subclinical autistic traits in nonclinical samples are poorly understood.

OBJECTIVE

To examine the familiality of Social Responsiveness Scale (SRS) scores of individuals with and without ASD.

DESIGN, SETTING, AND PARTICIPANTS

We performed a nested case-control study (pilot study: July 1, 2007, through June 30, 2009; full-scale study: September 15, 2008, through September 14, 2012) within a population-based longitudinal cohort. Participants were drawn from the Nurses' Health Study II, a cohort of 116,430 female nurses recruited in 1989. Case participants were index children with reported ASD; control participants were frequency matched by year of birth of case participants among those not reporting ASD. Of 3161 eligible participants, 2144 nurses (67.8%) returned SRS forms for a child and at least 1 parent and were included in these analyses.

EXPOSURE

The SRS scores, as reported by nurse mothers and their spouses, were examined in association with risk of ASD using crude and adjusted logistic regression analyses. The SRS scores of the children were examined in association with SRS scores of the parents using crude and adjusted linear regression analyses stratified by case status.

MAIN OUTCOMES AND MEASURES

Autism spectrum disorder, assessed by maternal report, validated in a subgroup with the Autism Diagnostic Interview-Revised.

RESULTS

A total of 1649 individuals were included in these analyses, including 256 ASD case participants, 1393 control participants, 1233 mothers, and 1614 fathers. Risk of ASD was increased by 85.0% among children whose parents had concordantly elevated SRS scores (odds ratio [OR], 1.85; 95% CI, 1.08-3.16) and by 52.0% when the score of either parent was elevated (OR, 1.52; 95% CI, 1.11-2.06). Elevated scores of the father significantly increased the risk of ASD in the child (OR, 1.94; 95% CI, 1.38-2.71), but no association was seen with elevated scores of the mother. Elevated parent scores significantly increased child scores in controls, corresponding to an increase in 23 points (P < .001).

CONCLUSIONS AND RELEVANCE

These findings support the role of additive genetic influences in concentrating inherited ASD susceptibility in successive generations and the potential role of preferential mating, and suggest that typical variation in parental social functioning can produce clinically significant differences in offspring social traits.

Sex-specific association of a common variant of the XG gene with autism spectrum disorders

Autism spectrum disorders (ASD) are much more common in males than in females. Studies using both linkage and candidate gene association approaches have identified genetic variants specific to families in which all affected cases were male, suggesting that sex may interact with or otherwise influence the expression of specific genes in association with ASD. In this study, we specifically evaluated the sex-specific genetic effects of ASD with a family-based genome-wide association study approach using the data from the Autism Genetic Resource Exchange repository. We evaluated the male-specific genetic effects of ASD in 374 multiplex families of European ancestry in which all affected were male (male-only; MO) and identified a novel genome-wide significant association in the pseudoautosomal boundary on chromosome Xp22.33/Yp11.31 in the MO families of predominantly paternal origin (rs2535443, p = 3.8 × 10(-8) ). Five markers that reside within a 550 kb intergenic region on chromosome 13q33.3, between the MYO16 and IRS2 genes, also showed suggestive association with ASD in the MO families (p = 3.3 × 10(-5) to 5.3 × 10(-7) ). In contrast, none of these markers appeared to be associated with ASD in the families containing any affected females. Our results suggest that the pseudoautosomal boundary on Xp22.33/Yp11.31 may harbor male-specific genetic variants for ASD.

Maternal dietary fat intake in association with autism spectrum disorders

Our goal in this study was to determine whether maternal fat intake before or during pregnancy was associated with risk of autism spectrum disorder (ASD) in the offspring. Our primary analysis included 317 mothers who reported a child with ASD and 17,728 comparison mothers from the Nurses' Health Study II (index births in 1991-2007). Dietary information was collected prospectively through a validated food frequency questionnaire. Binomial regression was used to estimate crude and adjusted risk ratios. Maternal intake of linoleic acid was significantly inversely associated with ASD risk in offspring, corresponding to a 34% reduction in risk in the highest versus lowest quartiles of intake. Mothers in the lowest 5% of ω-3 fatty acid intake had a significant increase in offspring ASD risk as compared with the remaining distribution (risk ratio = 1.53, 95% confidence interval: 1.00, 2.32); this association was also seen in the subgroup of women (86 cases and 5,798 noncases) for whom dietary information during pregnancy was available (risk ratio = 2.42, 95% confidence interval: 1.19, 4.91). Thus, variations in intake of polyunsaturated fats within the range commonly observed among US women could affect fetal brain development and ASD risk. Because the number of women with diet assessed during pregnancy was small, however, these results should be interpreted cautiously.

A study of the prevalence and risk factors leading to HIV infection among a sample of street children and youth of Kathmandu

Background

The true prevalence of HIV and other sexually transmitted diseases among street children in Nepal is virtually unknown while information on related behavioural risk factors in this population is non-existent. The risk of HIV infection among street children and adolescents may be especially high due to their marginalized social and economic conditions. This study was conducted to determine the prevalence of HIV infection among a sample of street children and youth of Kathmandu and to identify risk factors associated with HIV infection in this group.

A sample of street children and youth was recruited based on the purposive sampling of ten streets in Kathmandu, Nepal, known to have a high density of street children and youth. A total of 251 street children (aged 11–16 years) and youth (aged 17–24 years) were enrolled, with informed consent, from November, 2008 through June, 2009. Most of the participants (95%) were male. Case status was determined by serological assessment of HIV status; data on risk factors were obtained using structured survey interviews. HIV prevalence and rates of a number of behavioural risk factors suspected to play a role in HIV transmission among street children and youth were determined, including unprotected sex, intravenous drug use, and other risky sex and substance use behaviours.

Results

Among the 251 children and youth, we found an overall HIV prevalence of 7.6%. As the sample size of females was small (n = 13) and the behavioural risk factors are likely to be quite different for boys and girls, we conducted separate analyses by gender. As our small sample of females is unlikely to be representative and lacks power for statistical testing, our report focuses on the results for the males surveyed.The strongest behavioural risk factor to emerge from this study was intravenous drug use; 30% of the male subjects were injecting drug users and 20% of those were HIV positive. Furthermore, frequency of drug injection was a highly significant predictor with a dose–response relationship; males reporting occasional injection drug use were nearly 9 times more likely to be HIV positive than never users, while weekly drug injectors had over 46 times the risk of non-users, controlling for exposure to group sex, the only other significant risk factor in the multivariate model.

Conclusions

This sample of street children and youth of Kathmandu has a nearly 20-fold higher prevalence of HIV infection than the general population of Nepal (0.39%). The children and youth engage in number of high risk behaviours, including intravenous drug use, putting them at significant risk of contracting HIV and other sexually transmitted infections.

Brief report: no association between parental age and extreme social-communicative autistic traits in the general population

This is the first investigation of the relationship between parental age and extreme social-communicative autistic traits in the general population. The parents of 5,246 children in the Avon Longitudinal Study of Parents and Children (ALSPAC) completed the Social and Communication Disorders Checklist (SCDC). The association between parental age and SCDC scores was assessed in the full sample and among high scoring individuals (e.g. top 5%, 1%). There was no association between parental age and social-communicative autistic traits in the general population. Neither maternal nor paternal age was associated with extreme scores. These findings suggest that advanced parental age does not confer increased risk for extreme social and communication impairment assessed quantitatively.

Fertility therapies, infertility and autism spectrum disorders in the Nurses' Health Study II

BACKGROUND

An increasing number of women are utilizing fertility treatments, but little is known about their relation to autism spectrum disorders (ASD).

METHODS

To determine the association between maternal fertility therapy use and risk of having a child with ASD, we conducted a nested case-control study within the Nurses' Health Study II (n = 116,430). Maternally reported diagnoses of ASD were confirmed through a supplementary questionnaire and, in a subgroup, the Autism Diagnostic Interview-Revised. Controls were randomly selected by frequency matching to case children's year of birth. Associations were examined by self-reported infertility and type of therapy using conditional logistic regression.

RESULTS

In all, 9% of the 507 cases and 7% of 2,529 controls indicated fertility therapy use for the index pregnancy. No significant associations with self-reported fertility therapies or history of infertility were seen in primary analyses. In subgroup analyses of women with maternal age ≥ 35 years (n = 1,020), artificial insemination was significantly associated with ASD; ovulation inducing drug (OID) use was significantly associated in crude but not adjusted analyses (odds ratio 1.81, 95% CI 0.96-3.42). Results were similar by diagnostic subgroup, though within the advanced maternal age group, OID and artificial insemination were significantly associated with Asperger syndrome and pervasive developmental disorder not-otherwise specified, but not autistic disorder.

CONCLUSION

[corrected] Assisted reproductive therapy and history of infertility did not increase risk of having a child with ASD in this study. However, the associations observed with OID and artificial insemination among older mothers, for whom these exposures are more common, warrant further investigation.

Pregnancy complications and obstetric suboptimality in association with autism spectrum disorders in children of the Nurses' Health Study II

The authors examined pregnancy and obstetric complications in association with autism spectrum disorders (ASD) in children of participants from the Nurses' Health Study II, a prospective national cohort with information collected through biennial mailed questionnaires since 1989. Logistic regression was used to obtain crude and adjusted odds ratios for ASD, and by diagnostic subgroup. Seven hundred and ninety-three cases were reported among 66,445 pregnancies. Pregnancy complications and obstetric suboptimality factors were assessed by maternal report of occurrence in first birth and, in secondary analyses, in any birth. Complications and a suboptimality score were significantly associated with having a child with ASD (OR 1.49, 95% CI 1.26, 1.77, P<0.0001 for pregnancy complications in first birth and 2.76, 95% CI 2.04, 3.74, P<0.0001 comparing individuals with four or more obstetric suboptimality factors in first birth to those with none; results similar when assessed in any birth). In particular, gestational diabetes was associated with a significantly increased risk of ASD in results of primary and sensitivity analyses (OR in primary analysis = 1.76, 95% CI 1.34, 2.32, P<0.0001); suboptimal parity and suboptimal age-at-first-birth were also individual factors associated with ASD. Associations were similar by diagnostic subgroup, suggesting autism, Asperger syndrome, and other Pervasive Developmental Disorders are all associated with pregnancy complications. Consistent with previous research, the general class of pregnancy complications was associated with ASD as a whole. Additional work will be required to more fully assess the role of gestational diabetes.

Maternal early life factors associated with hormone levels and the risk of having a child with an autism spectrum disorder in the nurses health study II

It is not known whether reproductive factors early in the mother's life influence risk of autism spectrum disorders (ASD). We assessed maternal age at menarche, menstrual cycle characteristics during adolescence, oral contraceptive use prior to first birth, body shape, and body mass index (BMI) in association with ASD using binomial regression in a cohort study of 61,596 women, including 743 cases. Overall, early life factors were not associated with ASD, though early age at menarche (RR for age 10 or less = 1.54, 95% CI 1.18, 2.02, p = 0.0002) and BMI at age 18 of ≥30 (RR 2.03, 95% CI 1.34, 3.08, p = 0.0008) were significantly associated with increased risk of ASD. Further work should investigate the potential influence of these factors.

Common genetic variation in the GAD1 gene and the entire family of DLX homeobox genes and autism spectrum disorders

Biological and positional evidence supports the involvement of the GAD1 and distal-less homeobox genes (DLXs) in the etiology of autism. We investigated 42 single nucleotide polymorphisms in these genes as risk factors for autism spectrum disorders (ASD) in a large family-based association study of 715 nuclear families. No single marker showed significant association after correction for multiple testing. A rare haplotype in the DLX1 promoter was associated with ASD (P-value = 0.001). Given the importance of rare variants to the etiology of autism revealed in recent studies, the observed rare haplotype may be relevant to future investigations. Our observations, when taken together with previous findings, suggest that common genetic variation in the GAD1 and DLX genes is unlikely to play a critical role in ASD susceptibility.

Paternal age increases the risk for autism in an Iranian population sample

Background

Autism is a neurodevelopmental disorder which is known to have a strong genetic component and is most likely oligogenic. However, the necessary role of environmental factors has been well documented. Prior research suggests that parental characteristics, such as age and level of education, may be associated with a risk of autism. Parental age has been shown to be associated with many disorders, such as schizophrenia, childhood cancer and fetal death. However, results from studies of parental age and autism are inconsistent.

Methods

In the present study, we investigated the association of autism with parental age in 179 autism cases and 1611 matched cohort children from Iran. Each case was matched with nine cohort controls on parental education, sex, order of birth, consanguineous marriage, urbanism and province of residence. The Cox regression model was used to carry out conditional logistic regression on the matched data.

Results

There was a significant association between higher paternal age, but not maternal age, and an increasing risk of autism. An analysis of the combined effect of parental age and education also revealed that parents with higher education had an increased risk of having autistic children, with a dose-response effect of parental age.

Conclusions

This study, which is the first epidemiological study of autism in Iran, provides evidence of the association of paternal age and risk of autism.

Dissecting the phenotype in genome-wide association studies of psychiatric illness

Over the past 2 years genome-wide association studies have made major contributions to understanding the genetic architecture of many common human diseases. This editorial outlines the development of such studies in psychiatry and highlights the opportunities for advancing understanding of the biological underpinnings and nosological structure of psychiatric disorders.

A Discordant Sib-Pair Linkage Analysis of Age-Related Macular Degeneration

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness among older adults in the United States and throughout the developed world. Etiological research implicates both genetic and environmental components. Our prior genome scan in 511 affected sib-pairs and other relative pairs identified significant or suggestive linkage signals on chromosomes 1, 2, 3, 6, 8, 10, 12, 16, and 22.

PURPOSE

To search for genetic loci for AMD using the extremely discordant sib-pair (EDSP) method of linkage analysis, which until now has never been applied to the study of AMD.

METHODS

The EDSP method is a more powerful approach than standard methods which rely on relative pairs selected at random or pairs concordant for the phenotype. The EDSP approach has also been characterized as the only design that is uniformly powerful in nearly all genetic situations. Thus, substantial reductions in sample size can be achieved.

STUDY POPULATION

The study sample for analysis included 110 EDSPs from 40 families that comprise a subset of the 158 families studied in a prior genome-wide scan using affected relative pairs.

RESULTS

Evidence for linkage was found on chromosomes 1q, 2q, 6q, 19p, and 20q. The regions identified on chromosomes 1q and 2q were the same regions identified in our prior analysis, whereas the identified region on 6q was approximately 80 cM distal to our previous signal.

DISCUSSION

Within this study population, we have narrowed the focus to chromosomes 1q, 2q, 6q, 19p, and 20q in our search for AMD loci. However, given the fact that a gene was recently identified on chromosome 1q, future family- and population-based analyses should concentrate on testing for associations with candidate gene variants in the other identified chromosomal regions in searches for additional AMD loci.

Autism and serotonin transporter gene polymorphisms: a systematic review and meta-analysis

The serotonin transporter gene (5-HTT) plays a crucial role in serotonergic neurotransmission and has been found to be associated, with varying degrees of significance, with many diseases, including autism. Prior association studies of autism have yielded conflicting results regarding the association between two common 5-HTT polymorphisms, the promoter insertion/deletion (5-HTTLPR) and the intron 2 VNTR (STin2 VNTR). We conducted a systematic review and meta-analysis to test the following hypotheses: (i) there is an association between autism and either or both of the 5-HTTLPR and STin2 VNTR polymorphisms, and (ii) the S allele of 5-HTTLPR and/or the STin2.12 allele of the VNTR are the specific risk alleles for autism. All published family-based and population based studies were examined to determine the overall strength of association between 5-HTT polymorphisms and autism. After exclusion of studies with overlapping samples and studies whose data did not allow for calculation of an odds ratio, 16 studies were included for final analyses, all but two of which used a family-based design. The meta-analysis failed to find a significant overall association between either of the 5-HTT polymorphisms examined and autism. Further, no allelic transmission distortion was found when studies of simplex (11 studies) and multiplex (3 studies) family samples were analyzed separately. However, there was significant heterogeneity by ethnicity; family based studies of US mixed population samples showed preferential transmission of the S allele of 5-HTTLPR (S allele:L allele = 247:183), while there was no allelic distortion among the family-based studies of European and Asian samples.

Association between microdeletion and microduplication at 16p11.2 and autism

BACKGROUND

Autism spectrum disorder is a heritable developmental disorder in which chromosomal abnormalities are thought to play a role.

METHODS

As a first component of a genomewide association study of families from the Autism Genetic Resource Exchange (AGRE), we used two novel algorithms to search for recurrent copy-number variations in genotype data from 751 multiplex families with autism. Specific recurrent de novo events were further evaluated in clinical-testing data from Children's Hospital Boston and in a large population study in Iceland.

RESULTS

Among the AGRE families, we observed five instances of a de novo deletion of 593 kb on chromosome 16p11.2. Using comparative genomic hybridization, we observed the identical deletion in 5 of 512 children referred to Children's Hospital Boston for developmental delay, mental retardation, or suspected autism spectrum disorder, as well as in 3 of 299 persons with autism in an Icelandic population; the deletion was also carried by 2 of 18,834 unscreened Icelandic control subjects. The reciprocal duplication of this region occurred in 7 affected persons in AGRE families and 4 of the 512 children from Children's Hospital Boston. The duplication also appeared to be a high-penetrance risk factor.

CONCLUSIONS

We have identified a novel, recurrent microdeletion and a reciprocal microduplication that carry substantial susceptibility to autism and appear to account for approximately 1% of cases. We did not identify other regions with similar aggregations of large de novo mutations.

The Genetics of Age-Related Macular Degeneration: A Review of Progress to Date

Age-related macular degeneration (AMD) is the leading cause of vision loss and blindness among older adults in the USA and throughout the developed world. Etiological research suggests that AMD is a complex disease, caused by the actions and interactions of multiple genes and environmental factors. Familial aggregation studies, twin studies, and segregation analyses have provided strong evidence for the heritability of AMD, and linkage and association studies have been conducted to localize the disease-causing genes. Whole genome linkage scans have implicated nearly every chromosome in the human genome, with the most replicated signals residing on 1q25-31 and 10q26. Association studies have identified a major risk variant within the complement factor H gene (CFH), and recent reports suggest that PLEKHA1/LOC387715 and the BF/C2 regions may be major risk loci for AMD as well. Several other genes have had at least one positive association finding and deserve further exploration. Among these, apolipoprotein E (APOE) may be a minor risk locus. Additional genes will likely be identified, and future studies should explore the potential interactions of these genes with other genes as well as environmental factors.

Meta-analysis of genome scans of age-related macular degeneration

A genetic contribution to the development of age-related macular degeneration (AMD) is well established. Several genome-wide linkage studies have identified a number of putative susceptibility loci for AMD but only a few of these regions have been replicated in independent studies. Here, we perform a meta-analysis of six AMD genome screens using the genome-scan meta-analysis method, which allows linkage results from several studies to be combined, providing greater power to identify regions that show only weak evidence for linkage in individual studies. Results from non-parametric analysis for a broad AMD clinical phenotype (including two studies with quantitative traits) were extracted. For each study, 120 genomic bins of approximately 30 cM were defined and ranked according to maximum evidence for linkage within each bin. Bin ranks were weighted according to study size and summed across all studies; the summed rank (SR) for each bin was assessed empirically for significance using permutation methods. A high SR indicates a region with consistent evidence for linkage across studies. The strongest evidence for an AMD susceptibility locus was found on chromosome 10q26 where genome-wide significant linkage was observed (P=0.00025). Several other regions met the empirical significance criteria for bins likely to contain linked loci including adjacent pairs of bins on chromosomes 1q, 2p, 3p and 16. Several of the regions identified here showed only weak evidence for linkage in the individual studies. These results will help prioritize regions for future positional and functional candidate gene studies in AMD.

What is Known About Autism

Autism is a neurodevelopmental disorder of genetic origins, with a heritability of about 90%. Autistic disorder is classed within the broad domain of pervasive developmental disorders (PDD) that also includes Rett syndrome, childhood disintegrative disorder, Asperger syndrome, and PDD not otherwise specified (PDD-NOS). Prevalence estimates suggest a rate of 0.1-0.2% for autism and 0.6% for the range of PDD disorders. There is considerable phenotypic heterogeneity within this class of disorders as well as continued debate regarding their clinical boundaries. Autism is the prototypical PDD, and is characterized by impairments in three core domains: social interaction, language development, and patterns of behavior (restricted and stereotyped). Clinical pattern and severity of impairment vary along these dimensions, and the level of cognitive functioning of individuals with autism spans the entire range, from profound mental retardation to superior intellect. There is no single biological or clinical marker for autism, nor is it expected that a single gene is responsible for its expression; as many as 15+ genes may be involved. However, environmental influences are also important, as concordance in monozygotic twins is less than 100% and the phenotypic expression of the disorder varies widely, even within monozygotic twins. Multiple susceptibility factors are being explored using varied methodologies, including genome-wide linkage studies, and family- and case-control candidate gene association studies. This paper reviews what is currently known about the genetic and environmental risk factors, neuropathology, and psychopharmacology of autism. Discussion of genetic factors focuses on the findings from linkage and association studies, the results of which have implicated the involvement of nearly every chromosome in the human genome. However, the most consistently replicated linkage findings have been on chromosome 7q, 2q, and 15q. The positive associations from candidate gene studies are largely unreplicated, with the possible exceptions of the GABRB3 and serotonin transporter genes. No single region of the brain or pathophysiological mechanism has yet been identified as being associated with autism. Postmortem findings, animal models, and neuroimaging studies have focused on the cerebellum, frontal cortex, hippocampus, and especially the amygdala. The cerebello-thalamo-cortical circuit may also be influential in autism. There is evidence that overall brain size is increased in some individuals with autism. Presently there are no drugs that produce major improvements in the core social or pragmatic language deficits in autism, although several have limited effects on associated behavioral features. The application of new techniques in autism research is being proposed, including the investigation of abnormal regulation of gene expression, proteomics, and the use of MRI and postmortem analysis of the brain.

Examination of NRCAM, LRRN3, KIAA0716, and LAMB1 as autism candidate genes

BACKGROUND

A substantial body of research supports a genetic involvement in autism. Furthermore, results from various genomic screens implicate a region on chromosome 7q31 as harboring an autism susceptibility variant. We previously narrowed this 34 cM region to a 3 cM critical region (located between D7S496 and D7S2418) using the Collaborative Linkage Study of Autism (CLSA) chromosome 7 linked families. This interval encompasses about 4.5 Mb of genomic DNA and encodes over fifty known and predicted genes. Four candidate genes (NRCAM, LRRN3, KIAA0716, and LAMB1) in this region were chosen for examination based on their proximity to the marker most consistently cosegregating with autism in these families (D7S1817), their tissue expression patterns, and likely biological relevance to autism.

METHODS

Thirty-six intronic and exonic single nucleotide polymorphisms (SNPs) and one microsatellite marker within and around these four candidate genes were genotyped in 30 chromosome 7q31 linked families. Multiple SNPs were used to provide as complete coverage as possible since linkage disequilibrium can vary dramatically across even very short distances within a gene. Analyses of these data used the Pedigree Disequilibrium Test for single markers and a multilocus likelihood ratio test.

RESULTS

As expected, linkage disequilibrium occurred within each of these genes but we did not observe significant LD across genes. None of the polymorphisms in NRCAM, LRRN3, or KIAA0716 gave p < 0.05 suggesting that none of these genes is associated with autism susceptibility in this subset of chromosome 7-linked families. However, with LAMB1, the allelic association analysis revealed suggestive evidence for a positive association, including one individual SNP (p = 0.02) and three separate two-SNP haplotypes across the gene (p = 0.007, 0.012, and 0.012).

CONCLUSIONS

NRCAM, LRRN3, KIAA0716 are unlikely to be involved in autism. There is some evidence that variation in or near the LAMB1 gene may be involved in autism.

A QTL genome scan of the metabolic syndrome and its component traits

BACKGROUND

Because high blood pressure, altered lipid levels, obesity, and diabetes so frequently occur together, they are sometimes collectively referred to as the metabolic syndrome. While there have been many studies of each metabolic syndrome trait separately, few studies have attempted to analyze them combined, i.e., as one composite variable, in quantitative trait linkage or association analysis. We used genotype and phenotype data from the Framingham Heart Study to perform a full-genome scan for quantitative trait loci underlying the metabolic syndrome.

RESULTS

Heritability estimates for all of the covariate-adjusted and age- and gender-standardized individual traits, and the composite metabolic syndrome trait, were all fairly high (0.39-0.62), and the composite trait was among the highest at 0.61. The composite trait yielded no regions with suggestive linkage by Lander and Kruglyak's criteria, although there were several noteworthy regions for individual traits, some of which were also observed for the composite variable.

CONCLUSION

Despite its high heritability, the composite metabolic syndrome trait variable did not increase the power to detect or localize linkage peaks in this sample. However, this strategy and related methods of combining correlated individual traits deserve further investigation, particularly in settings with complex causal pathways.

Intergenerational transmission of tobacco use and dependence: A transdisciplinary perspective

Numerous questions remain regarding the intergenerational transmission of tobacco use and dependence, and some of these questions are best approached from a transdisciplinary perspective. For example, considering both genetic and environmental influences on cigarette smoking promises to be a fruitful venue for future investigations. In this paper, we consider the evidence regarding intergenerational influences on the transmission of tobacco use and nicotine dependence in both humans and animal models; our focus will be on genetic influences, in utero exposure to nicotine, and some postnatal influences. Research gaps that exist between scientific disciplines are highlighted, and some directions for future research are suggested.

A genomewide scan for age-related macular degeneration provides evidence for linkage to several chromosomal regions

We report the results of a genomewide scan for age-related macular degeneration (AMD) in 158 multiplex families. AMD classification was based on fundus photography and was assigned a grade ranging from 1 (no disease) to 5 (exudative disease). Genotyping was performed by the National Heart, Lung, and Blood Institute Mammalian Genotyping Service at Marshfield (404 short tandem repeat markers). The sample included 158 families with two or more siblings with AMD, 490 affected individuals, 101 unaffected individuals, and 38 whose affection status was unknown. Relative pairs included 511 affected sibling, 28 avuncular, 53 cousin, 7 grandparent-grandchild, and 9 grand-avuncular pairs. Two-point parametric and multipoint parametric and nonparametric analyses were performed. Maximum two-point LOD scores of 1.0-2.0 were found for markers on chromosomes 1, 2, 8, 10, 14, 15, and 22. Multipoint analyses were consistent with the two-point results for chromosomes 1, 2, 8, 10, and 22 and provided evidence for additional linkage regions on chromosomes 3, 6, 8, 12, 16, and X. Our signals on chromosomes 1q, 6p, and 10q are consistent with some other previously published results. Significant linkage to AMD was found for one marker on chromosome 2, two adjacent markers on chromosome 3, two adjacent markers on chromosome 6, and seven contiguous markers on chromosome 8, with empirical P values of .00001. The consistency of many of the other signals across both two-point and multipoint, as well as parametric and nonparametric, analyses indicate several other regions worthy of follow-up.

Defining the autism minimum candidate gene region on chromosome 7

Previous genetic and cytogenetic studies provide evidence that points to one or more autism susceptibility genes residing on chromosome 7q (AUTS1, 115-149 cM on the Marshfield map). However, further localization using linkage analysis has proven difficult. To overcome this problem, we examined the Collaborative Linkage Study of Autism (CLSA) data-set to identify only the families potentially linked to chromosome 7. Out of 94, 47 families were identified and 17 markers were used to generate chromosomal haplotypes. We performed recombination breakpoint analysis to determine if any portion of the chromosome was predominately shared across families. The most commonly shared region spanned a 6 cM interval between D7S501 and D7S2847. Additional markers at 1 cM intervals within this region were genotyped and association and recombination breakpoint analysis was again performed. Although no significant allelic association was found, the recombination breakpoint data points to a shared region between D7S496-D7S2418 (120-123 cM) encompassing about 4.5 Mb of genomic DNA containing over 50 genes.

On the detection of linkage in multiple data sets: a comparison of various statistical approaches

We contrast the pooling of multiple data sets with the compound HLOD (HLOD-C) and the posterior probability of linkage (PPL), two approaches that have been shown to have more power in the presence of genetic heterogeneity. We also propose and evaluate several multipoint extensions.

Linkage disequilibrium at the Angelman syndrome gene UBE3A in autism families

Autistic disorder is a neurodevelopmental disorder with a complex genetic etiology. Observations of maternal duplications affecting chromosome 15q11-q13 in patients with autism and evidence for linkage and linkage disequilibrium to markers in this region in chromosomally normal autism families indicate the existence of a susceptibility locus. We have screened the families of the Collaborative Linkage Study of Autism for several markers spanning a candidate region covering approximately 2 Mb and including the Angelman syndrome gene (UBE3A) and a cluster of gamma-aminobutyric acid (GABA(A)) receptor subunit genes (GABRB3, GABRA5, and GABRG3). We found significant evidence for linkage disequilibrium at marker D15S122, located at the 5' end of UBE3A. This is the first report, to our knowledge, of linkage disequilibrium at UBE3A in autism families. Characterization of null alleles detected at D15S822 in the course of genetic studies of this region showed a small (approximately 5-kb) genomic deletion, which was present at somewhat higher frequencies in autism families than in controls.

Probabilistic diagnosis in linkage analysis of bipolar disorder: putting weights on the fringe

We explored the utility of probabilistic weighting of fringe phenotypes in linkage analysis of bipolar disorder for the GAW10 chromosome 18 data. Four liability classes were assigned probabilistic weights based on the estimated probability that the case was a true bipolar. The weights were incorporated in parametric and nonparametric, single and multipoint analyses.

Impact of maternal depression on ratings of comorbid depression in adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

To assess the degree to which indirect maternal reports of comorbid major depression (MD) in adolescents with and without attention-deficit/hyperactivity disorder (ADHD) were influenced by the mother's personal history of MD.

METHOD

Bivariate regression was used to model the impact of maternal depression on the direct and indirect report of MD in ADHD (n = 150) and non-ADHD (n = 123) subjects. The dependent variable (i.e., risk for MD) was modeled as a function of the main effect of ADHD, the main effect of reporter, their interaction, and higher-order interactions with maternal depression.

RESULTS

There was a significant interaction between maternal depression and the effect of reporter exclusively in non-ADHD control subjects. ADHD continued to be a significant risk factor for MD independent of maternal reporting or maternal depression.

CONCLUSIONS

The potential distortion of indirect interviews by depressed mothers may be stronger in community than in clinical settings and does not account for the increased risk for MD in referred adolescents with ADHD.

The importance of watching our weights: how the choice of weights for non-independent sib pairs can dramatically alter results

Handling non-independent sib pairs in families with multiple affected sibs presents a problem in likelihood-based nonparametric linkage analyses. We contrast the more stable partial-likelihood solution in MAPMAKER/SIBS with the extremely variable partial-likelihood approach used in ASPEX, and the potential inflation of lods when the problem is ignored as in BETA.

An autosomal genomic screen for autism. Collaborative linkage study of autism

Autism is a severe neurodevelopmental disorder defined by social and communication deficits and ritualistic-repetitive behaviors that are detectable in early childhood. The etiology of idiopathic autism is strongly genetic, and oligogenic transmission is likely. The first stage of a two-stage genomic screen for autism was carried out by the Collaborative Linkage Study of Autism on individuals affected with autism from 75 families ascertained through an affected sib-pair. The strongest multipoint results were for regions on chromosomes 13 and 7. The highest maximum multipoint heterogeneity LOD (MMLS/het) score is 3.0 at D13S800 (approximately 55 cM from the telomere) under the recessive model, with an estimated 35% of families linked to this locus. The next highest peak is an MMLS/het score of 2.3 at 19 cM, between D13S217 and D13S1229. Our third highest MMLS/het score of 2.2 is on chromosome 7 and is consistent with the International Molecular Genetic Study of Autism Consortium report of a possible susceptibility locus somewhere within 7q31-33. These regions and others will be followed up in the second stage of our study by typing additional markers in both the original and a second set of identically ascertained autism families, which are currently being collected. By comparing results across a number of studies, we expect to be able to narrow our search for autism susceptibility genes to a small number of genomic regions. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:609-615, 1999.

Predictors of cognitive test patterns in autism families

In a case-control study of cognitive performance, tests of intelligence, reading, spelling, and pragmatic language were administered to the parents and siblings of 90 community-ascertained probands with autism (AU group) and to the parents and siblings of 40 similarly ascertained probands with trisomy 21 Down syndrome (DS group). The two samples were comparable for age and parents' education; both groups were well-educated and had above-average intelligence. AU parents scored slightly but significantly lower on the WAIS-R Full Scale and Performance IQ, on two subtests (Picture Arrangement and Picture Completion), and on the Word Attack Test (reading nonsense words) from the Woodcock-Johnson battery. There were no differences between AU and DS siblings. As in earlier studies, AU parents, more often than DS parents, reported a history of early language-related cognitive difficulties; we were not able to replicate this in siblings. AU parents who reported such difficulties scored significantly lower on Verbal IQ, spelling, and the nonsense reading test. AU parents without a history of early language-related cognitive difficulties often had a Verbal IQ that exceeded Performance IQ by more than one standard deviation. AU siblings with early language-related difficulties had similar findings: lower Verbal IQ, poorer spelling, and poorer reading scores, compared to AU siblings without such a history. Parents with a positive history also scored worse on a measure of pragmatic language,the Pragmatic Rating Scale, but not on measures of social-related components of the broader autism phenotype. We propose that cognitive differences in a subset of autism family members are manifestations of the language-related component of the broader autism phenotype, and separate from the social-related component. This is consistent with the hypothesis that there are several genes that may interact to cause autism which segregate independently and have distinguishable manifestations in family members. The hypothesis would be further supported by finding different patterns of genetic loci linked to autism in families where one or both parents has language difficulties.

Finding specific genes that cause autism: a combination of approaches will be needed to maximize power

Although autism is clearly inherited, it may be challenging to find the genes involved: The mechanism of inheritance is unknown, families with an autistic child are usually small, parent-child pairs are rare, and a fairly large number of genes may be involved, some or all of which may have a small effect on the phenotype. We discuss several strategies for finding genes, all of which may be used in combination to find the relevant genes.

Finding specific genes that cause autism: a combination of approaches will be needed to maximize power

Although autism is clearly inherited, it may be challenging to find the genes involved: The mechanism of inheritance is unknown, families with an autistic child are usually small, parent-child pairs are rare, and a fairly large number of genes may be involved, some or all of which may have a small effect on the phenotype. We discuss several strategies for finding genes, all of which may be used in combination to find the relevant genes.

Macrocephaly in children and adults with autism

OBJECTIVE

To explore the frequency and onset of macrocephaly in autism and its relationship to clinical features.

METHOD

Head circumferences at birth, during early childhood, and at the time of examination were studied in a community-based sample of autistic children and adults. The authors investigated whether head circumference at the time of examination was associated with clinical features.

RESULTS

Fourteen percent of the autistic subjects had macrocephaly: 11% of males and 24% of females. In most, the macrocephaly was not present at birth; in some it became apparent in early and middle childhood as a result of increased rate of head growth. A small relationship was noted between head circumference percentile and less severe core features of autism. Neither macrocephaly nor head circumference percentile was associated with nonverbal IQ, verbal status, seizure disorder, neurological soft signs or minor physical anomalies in the autistic subjects.

CONCLUSION

Macrocephaly is common in autism and usually is not present at birth. Rates of head growth may be abnormal in early and middle childhood in some (37%) children with autism. Macrocephaly does not define a homogeneous subgroup of autistic individuals according to clinical features.

Self-mutilation and suicide attempt: distinguishing features in prisoners

Nonlethal forms of self-injury are often discussed together with suicide attempts as though they belonged on a continuum of self-harm. Both types of self-injury are common in prisons, which have a predominantly male population; however, most studies of nonlethal self-injury have been done with female subjects. This exploratory study tested the hypothesis that prisoners who injured themselves without intending to die would differ clinically from prisoners who had attempted suicide. Inmates admitted to the prison unit of a public hospital for treatment of self-inflicted wounds or who had a history of previous self-injury were administered a standardized intake protocol by the first author, which included asking about their intent at the time they injured themselves. Patients were classified as self-mutilators or suicide attempters on the basis of intent. Fifteen patients reported that they had attempted to take their own lives, while 16 reported other reasons for harming themselves. Suicide attempt was associated with adult affective disorder 13/15 versus 2/16 mutilators); self-mutilation with a history of childhood hyperactivity (12/16 versus 1/15 suicide attempters) and a mixed dysthymia/anxiety syndrome that began in childhood or early adolescence (9/16). Prison self-mutilators and suicide attempters had very different clinical presentations and histories. The history of childhood hyperactivity in self-mutilators deserves further study in both correctional and noncorrectional populations.

Assessing risk for the Tourette spectrum of disorders among first-degree relatives of probands with Tourette syndrome

Previous studies have indicated that genetic investigations of Tourette syndrome (TS) should focus on a phenotype that includes not only TS, but chronic tics (CT) and obsessive-compulsive disorder (OCD) as well. These studies have shown that sex may play a role in determining which of the disorders in the TS spectrum is expressed in a susceptible individual. Female relatives of TS probands far more often express OCD, while male relatives more often express TS or CT. Data from the Yale Family Study of TS were used to model risk to first-degree relatives of probands with TS for a variety of TS disease phenotypes. Risk to relatives was modeled using multivariate Cox regression analysis, a method appropriate for assessing risk when there is correlation among disease onsets. This is the first known application of this method to family data. The study identified two proband characteristics that increase the risk for disease onset among both male and female relatives for all TS spectrum disorders, lending credence to the hypothesis that TS spectrum disorders share a common etiology. These were a relatively younger age-at-onset, and no experience of simple motor tics. The predictive ability of two additional factors varied by both sex and disease phenotype. These characteristics, i.e., proband onset with compulsive tics, and proband onset with range, appear to increase risk primarily in female relatives, and for the OCD part of the spectrum.

Clinical correlates of enuresis in ADHD and non-ADHD children

Enuresis and attention deficit hyperactivity disorder (ADHD) are common childhood disorders that often co-occur. Although each has been linked to neurodevelopmental immaturity and increased risk for psychopathology, the clinical correlates of enuresis remain unclear. Subjects were 140 6-17-year-old boys with DSM-III-R ADHD and 120 non-ADHD controls. Information on enuresis and psychiatric diagnoses was obtained in a standardized manner blind to the child's clinical status. Our results show that (1) enuresis did not increase the risk for psychopathology in children with or without ADHD; (2) enuresis was not associated with psychosocial adversity or developmental immaturity; (3) enuresis was associated with increased risk for learning disability, impaired intellectual functioning, and impaired school achievement in normal control children but not in children with ADHD; and (4) the same pattern of findings was obtained after stratifying children with enuresis by primary versus secondary and by nocturnal versus diurnal subtypes. These results suggest that the clinical implications of enuresis may differ for ADHD and non-ADHD children.

Tourette's syndrome: what are the influences of gender and comorbid obsessive-compulsive disorder?

OBJECTIVE

To explore the influence of gender and comorbid obsessive-compulsive disorder (OCD) on the phenomenology of Tourette's syndrome (TS).

METHOD

TS proband groups defined by gender and comorbid OCD status were compared on a variety of sociodemographic variables, clinical characteristics, and perinatal complications.

RESULTS

Compared to females, males more often onset with rage and had ever experienced any form of simple tics. Females onset with compulsive tics more often than males. Probands with comorbid OCD were more likely than those without OCD to onset with complex tics. Delivery complications, especially forceps deliveries, were associated with being male and with having OCD. Fetal exposure to relatively high levels of coffee, cigarettes, or alcohol predicted OCD in TS probands. Diagnosis of TS occurred at later ages among females than among males. Males and females displayed different age distributions.

CONCLUSIONS

Males and females tend to experience different kinds of symptoms at onset. However, the overall experience of TS appears to be similar for both groups. Perinatal brain injury is implicated in the etiology of TS in some boys. Early brain injury may cause or exacerbate the development of OCD in some TS sufferers.

Gender and mortality in schizophrenia: do women act like men?

The effect of gender on mortality was explored for a sample of DSM-III diagnosed schizophrenics followed for up to 42 years. The data for 332 cases and 304 matched normal controls were from the retrospective cohort family studies, the Iowa 500 and non-500. Survival analysis and Cox regression models were used to test the effects of gender, illness status and their interaction on the risks for natural and unnatural deaths. The control men experienced significantly more unnatural deaths than the control women, which was not found for schizophrenic men and women. The unnatural death rate among schizophrenic women was similar to the rate for schizophrenic and control men, and significantly higher than for control women during the early phase of the illness. Findings suggest that some factors that predict suicide may be similar for schizophrenic women and men.

The role of gender in identifying subtypes of schizophrenia: a latent class analytic approach

Past literature suggests that schizophrenic men and women may be at different risks for developing different subtypes of schizophrenia. This hypothesis was tested using data from the well-known retrospective cohort family studies, the Iowa 500 and the Iowa non-500. The sample consisted of 171 male and 161 female DSM-III schizophrenic patients and 713 of their first-degree relatives. First, bivariate tests for gender differences were conducted regarding family morbidity, age of onset, premorbid history, season of birth, and expression of deficit and affective symptoms. Restricted maximum likelihood latent class analysis was then used to test whether there was a subgroup of schizophrenic men who were more likely to have a low familial risk for schizophrenia or schizophrenia spectrum disorders, deficit symptoms, poor premorbid history, and birth in the winter months, suggesting possible early environmental insults, compared to schizophrenic women. Results showed that although men were more likely to meet these criteria, women also met them, thus suggesting gender differences in the prevalence of the subtype. Schizophrenic women were more likely to express a form of the illness characterized by dysphoria, persecutory delusions, and a higher family morbidity risk for schizophrenia than schizophrenic men. Results for spectrum disorders among relatives were equivocal with regard to gender.