George T. Capone

Autism spectrum disorder in fragile X syndrome: Communication, social interaction, and specific behaviors

The present study extends our previous work on social behavior impairment in young males with fragile X syndrome (FraX). Specifically, we evaluated whether the autistic phenomenon in FraX is expressed as a range of behavioral impairments as in idiopathic autism (Aut). We also examined whether there are behaviors, identified as items of the Autism Diagnostic Interview‐Revised (ADI‐R), that in FraX predispose to or differentiate subjects with autism spectrum disorder (ASD) diagnosis. Finally, regression models were utilized to test the relative contribution of reduced communication and socialization skills to ADI‐R scores and diagnoses. A cohort of 56 boys (3–8 years) with FraX was examined in terms of scores on measures of cognition (IQ was a co‐variate in most analyses.), autistic behavior, problem/aberrant behavior, adaptive behavior, and language development. We found that, indeed, in terms of problem behavior and adaptive skills, there is a range of severity from FraX + Aut to FraX + PDD (Pervasive Developmental Disorder) to FraX + none. ADI‐R items representing “Play” types of interaction appear to be “susceptibility” factors since they were abnormal across the FraX cohort. Integrated regression models demonstrated that items reflecting complex social interaction differentiated the FraX + ASD (Aut + PDD) subgroup from the rest of the FraX cohort, while abnormalities in basic verbal and non‐verbal communication distinguished the most severely affected boys with FraX + Aut from the milder FraX + PDD cohort. Models incorporating language, adaptive communication, and adaptive socialization skills revealed that socialization was not only the main influence on scores but also a predictor of ASD diagnosis. Altogether, our findings demonstrate that the diagnosis of ASD in FraX reflects, to a large extent, an impairment in social interaction that is expressed with variable severity in young males with FraX.

Precision and error of three-dimensional phenotypic measures acquired from 3dMD photogrammetric images

The genetic basis for complex phenotypes is currently of great interest for both clinical investigators and basic scientists. In order to acquire a thorough understanding of the translation from genotype to phenotype, highly precise measures of phenotypic variation are required. New technologies, such as 3D photogrammetry are being implemented in phenotypic studies due to their ability to collect data rapidly and non‐invasively. Before these systems can be broadly implemented, the error associated with data collected from images acquired using these technologies must be assessed. This study investigates the precision, error, and repeatability associated with anthropometric landmark coordinate data collected from 3D digital photogrammetric images acquired with the 3dMDface System. Precision, error due to the imaging system, error due to digitization of the images, and repeatability are assessed in a sample of children and adults (n = 15). Results show that data collected from images with the 3dMDface System are highly repeatable and precise. The average error associated with the placement of landmarks is sub‐millimeter; both the error due to digitization and due to the imaging system are very low. The few measures showing a higher degree of error include those crossing the labial fissure, which are influenced by even subtle movement of the mandible. These results suggest that 3D anthropometric data collected using the 3dMDface System are highly reliable and, therefore, useful for evaluation of clinical dysmorphology and surgery, analyses of genotype‐phenotype correlations, and inheritance of complex phenotypes.

Specificity of Cerebellar Vermian Abnormalities in Autism: A Quantitative Magnetic Resonance Imaging Study

To gain insight into the specificity of cerebellar vermian abnormalities reported in autism, we conducted a magnetic resonance imaging (MRI) study of boys with either of two conditions associated with autism, Down syndrome and fragile X syndrome, compared with boys with idiopathic autism and controls. The subjects, ranging in age from 3 to 9 years, included 16 boys with Down syndrome + autism and 11 boys with Down syndrome only; 13 boys with fragile X syndrome + autism and 9 boys with fragile X syndrome only; 10 boys with idiopathic autism; and 22 controls. Diagnosis of autism was based on DSM-IV criteria, confirmed primarily by the Autism Diagnostic Interview. T1-weighted midsagittal MRIs were used to measure midline structures. Intracranial area, reflecting brain size, was significantly smaller in subjects with Down syndrome. Therefore, all vermian measures were expressed as ratios to intracranial area. Analysis of covariance (covarying for age and IQ) demonstrated that posterior vermi (lobules VI—VII and VIII—X) were markedly smaller in both Down syndrome groups and those with fragile X syndrome only, whereas only lobules VI—VII were reduced in idiopathic autism. Factorial analyses of variance tested interactions between autism factor and the diagnosis of Down syndrome or fragile X syndrome. The size of lobules VI—VII/intracranial area was dependent on autism status only in fragile X syndrome, with ratios significantly larger in fragile X syndrome with autism with respect to fragile X syndrome only. We conclude that selective posterior vermis hypoplasia is seen not only in idiopathic autism but also in Down syndrome and some individuals with fragile X syndrome. However, reductions in vermian lobules VI and VII appear to be specific to idiopathic autism, whereas increased size of lobules VI and VII is associated with autism in fragile X syndrome. The latter results are consistent with MRI studies showing lobules VI—VII hyperplasia in a subset of subjects with idiopathic autism and cerebral and hippocampal enlargements in fragile X syndrome. (J Child Neurol 2003;18:463—470).

Behavior problems of children with Down syndrome and life events

Behavior problems of 44 children with Down syndrome between the ages of 6 and 15 and 44 controls without mental retardation matched for age, sex, and socioeconomic status were compared on the basis of mother and teacher ratings. Ratings from both sources indicated that children with Down syndrome had more behavior problems, in particular attention deficit, noncompliance, thought disorder, and social withdrawal. Life events from the past year were significantly associated with mother but not teacher ratings of Down syndrome behavior problems.

Down syndrome: advances in molecular biology and the neurosciences.

The entire DNA sequence for human chromosome 21 is now complete, and it is predicted to contain only about 225 genes, which is approximately three-fold fewer than the number initially predicted just 10 years ago. Despite this remarkable achievement, very little is known about the mechanism(s) whereby increased gene copy number (gene dosage) results in the characteristic phenotype of Down syndrome. Although many of the phenotypic traits show large individual variation, neuromotor dysfunction and cognitive and language impairment are observed in virtually all individuals. Currently, there are no efficacious biomedical treatments for these central nervous system-associated impairments. To develop novel therapeutic strategies, the effects of gene dosage imbalance need to be understood within the framework of those critical biological events that regulate brain organization and function.

Down syndrome and comorbid autism-spectrum disorder: Characterization using the aberrant behavior checklist

To report on the cognitive and behavioral attributes of 61 children with Down syndrome (DS) and autistic‐spectrum disorder (ASD) according to DSM‐IV criteria; to determine the utility of the aberrant behavior checklist (ABC) to characterize these subjects for research purposes; and to test the hypothesis that subjects with DS + ASD could be distinguished from their typical DS peers using the ABC. Cross‐sectional design. Cases with DS + ASD (N = 61), comparison group of DS + stereotypy movement disorder (SMD) (N = 26) and typical DS controls without behavior problems (N = 44) were ascertained and enrolled sequentially upon presentation to a DS clinic at an academic medical center over a 10‐year period from 1991 to 2001. All subjects underwent neurodevelopmental and medical evaluation, and standardized cognitive testing. The parents provided responses to standardized behavioral questionnaires. Cognitive function (IQ) differed markedly across the three groups. The Lethary and Stereotypy subscales of the ABC were highly significant (P < 0.001) in distinguishing the three groups from one another. Within the ASD group differences were apparent by DSM‐IV type on the Lethargy subscale, which reached significance, ANOVA (F = 0.002) and t‐test (Autism > PDD, P = 0.005; PDD < CDD, P = 0.002). Using a multivariate regression model, the ABC scales alone explained 62% of variance of ASD outcome; addition of demographic variables explained up to 68% of the variance. There is good correlation between DSM‐IV criteria for autism and subscales scores on the ABC in subjects with DS. This study demonstrates the feasibility of using the ABC to characterize the neurobehavioral phenotype of a cohort of children with trisomy 21 and ASD for ongoing research purposes.

Neurobehavioral disorders in children, adolescents, and young adults with Down syndrome†

The term dual‐diagnosis refers to a person with mental retardation and a psychiatric disorder. Most children with Down syndrome (DS) do not have a psychiatric or neurobehavioral disorder. Current prevalence estimates of neurobehavioral and psychiatric co‐morbidity in children with DS range from 18% to 38%. We have found it useful to distinguish conditions with a pre‐pubertal onset from those presenting in the post‐pubertal period, as these are biologically distinct periods each with a unique vulnerability to specific psychiatric disorders. Due to the increased recognition that psychiatric symptoms may co‐occur with mental retardation, and are not inextricably linked to cognitive impairment, these conditions are considered treatable, in part, under a medical model. Improvement in physiologic regulation, emotional stability, and neurocognitive processing is one of the most elusive but fundamental goals of pharmacologic intervention in these disorders.

Variation in folate pathway genes contributes to risk of congenital heart defects among individuals with Down syndrome

Cardiac abnormalities are one of the most common congenital defects observed in individuals with Down syndrome. Considerable research has implicated both folate deficiency and genetic variation in folate pathway genes with birth defects, including both congenital heart defects (CHD) and Down syndrome (DS). Here, we test variation in folate pathway genes for a role in the major DS‐associated CHD atrioventricular septal defect (AVSD). In a group of 121 case families (mother, father, and proband with DS and AVSD) and 122 control families (mother, father, and proband with DS and no CHD), tag SNPs were genotyped in and around five folate pathway genes: 5,10‐methylenetetrahyrdofolate reductase (MTHFR), methionine synthase (MTR), methionine synthase reductase (MTRR), cystathionine β‐synthase (CBS), and the reduced folate carrier (SLC19A1, RFC1). SLC19A1 was found to be associated with AVSD using a multilocus allele‐sharing test. Individual SNP tests also showed nominally significant associations with odds ratios of between 1.34 and 3.78, depending on the SNP and genetic model. Interestingly, all marginally significant SNPs in SLC19A1 are in strong linkage disequilibrium (r2≥0.8) with the nonsynonymous coding SNP rs1051266 (c.80A>G), which has previously been associated with nonsyndromic cases of CHD. In addition to SLC19A1, the known functional polymorphism MTHFR c.1298A was over‐transmitted to cases with AVSD (P=0.05) and under‐transmitted to controls (P=0.02). We conclude, therefore, that disruption of the folate pathway contributes to the incidence of AVSD among individuals with DS. Genet. Epidemiol. 34: 603–612, 2010.

Postnatal diagnosis of Down syndrome: Synthesis of the evidence on how best to deliver the news

CONTEXT: Many parents of children with Down syndrome (DS) have expressed dissatisfaction with how they learned about their childs diagnosis. DS remains the most common chromosomal condition, occurring in 1 of every 733 births, with the majority of children still diagnosed postnatally. OBJECTIVE: Our goal was to review systematically all available evidence regarding how physicians should approach the conversation in which they explain DS for the first time to new parents. METHODS: We searched online databases from 1960 to 2008, including Medline and PsychInfo, as well as Web sites maintained by academic organizations (eg, American Academy of Pediatrics) and other nonprofit or private organizations (eg, the National Down Syndrome Society), by using the terms “Down syndrome,” “trisomy 21,” “mongolism,” “prenatal diagnosis,” “postnatal care,” and “delivery of health care.” Articles were selected that answered ≥1 research question, established a priori: (1) Who is the best person to communicate the news? (2) When is the best time to share the news? (3) Where is the best place or setting to deliver the news? (4) What information should be delivered? and (5) How should the news be communicated? All studies were evaluated for quality according to the method outlined by the US Preventative Services Task Force. Final recommendations were based on the strength of evidence. RESULTS: Parents prefer to receive the diagnosis together in a joint meeting with their obstetrician and pediatrician. The conversation should take place in a private setting as soon as a physician suspects a diagnosis of DS. Accurate and up-to-date information should be conveyed, including information about local support groups and resources. CONCLUSION: By implementing a few cost-neutral measures, physicians can deliver a postnatal diagnosis of DS in a manner that will be deemed by new parents as sensitive and appropriate.

Autistic-Spectrum Disorders in Down Syndrome: Further Delineation and Distinction from Other Behavioral Abnormalities

The present study extends our previous work characterizing the behavioral features of autistic‐spectrum disorder (ASD) in Down syndrome (DS) using the Aberrant Behavior Checklist (ABC) and Autism Behavior Checklist (AutBehav). We examined which specific behaviors distinguished the behavioral phenotype of DS + ASD from other aberrant behavior disorders in DS, by determining the relative contribution of ABC and AutBehav subscales and items to the diagnosis of ASD. A total of 127 subjects (aged 2–24 years; mean age: 8.4 years; ∼70% male), comprising: a cohort of 64 children and adolescents with DS and co‐morbid ASD (DS + ASD), 19 with DS and stereotypic movement disorder (DS + SMD), 18 with DS and disruptive behaviors (DS + DB), and 26 with DS and no co‐morbid behavior disorders (DS + none) were examined using the aforementioned measures of aberrant behavior. We found that subjects with DS + ASD showed the most severe aberrant behavior, especially stereotypy compared to DS + none and lethargy/social withdrawal and relating problems compared to DS + SMD. Specifically, relatively simple stereotypic behavior differentiated DS + ASD from DS + DB, whereas odd/bizarre stereotypic and anxious behavior characterized DS + ASD relative to DS + SMD and DS + none. Additionally, in a subset of subjects with DS + ASD and anxiety, social withdrawal was particularly pronounced. Overall, our findings indicate that a diagnosis of DS + ASD represents a distinctive set of aberrant behaviors marked by characteristic odd/bizarre stereotypic behavior, anxiety, and social withdrawal.