Article

Infant head growth in male siblings of children with and without autism spectrum disorders

Departments of Psychiatry and Pediatrics, Washington University, Saint. Louis, Missouri.
Journal of Neurodevelopmental Disorders (Impact Factor: 3.71). 03/2010; 2(1):39-46. DOI: 10.1007/s11689-009-9036-5
Source: PubMed

ABSTRACT PURPOSE: Previous research has indicated that children with autism exhibit accelerated head growth (HG) in infancy, although the timing of acceleration varies between studies. We examined infant HG trajectory as a candidate autism endophenotype by studying sibling pairs. METHODS: We retrospectively obtained serial head orbitofrontal circumference measurements of: a) 48 sibling pairs in which one (n=28) or both (n=20) sibs were affected by an autism spectrum disorder (ASD); and b) 85 control male sibling pairs. RESULTS: Rate of HG of ASD subjects was slightly accelerated compared to controls, but the magnitude of difference was below the limit of reliability of standard measurement methods. Sibling intra class correlation for rate of HG was highly statistically significant; the magnitude was significantly stronger among autism-affected families (ICC=.63) than among controls (ICC=.26), p<.01. CONCLUSION: Infant HG trajectory appears familial-possibly endophenotypic-but was not a reliable marker of autism risk among siblings of ASD probands in this sample.

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    • "ements and overall growth measurements must be recorded and controlled for before comparing head size between groups of children . Additional factors such as diet , activity levels , and medication side effects , ideally should also be taken into account . The use of control groups not representative of the general population is also problematic ( Constantino et al . , 2010a ; Mraz et al . , 2009 ; Raznahan et al . , 2013 ; Zwaigenbaum et al . , 2014 ) . When compared with CDC norms , local control groups of TD children differ quite dramatically in HC , weight , and stature , suggesting that either the TD samples were not representative of the population , or that the CDC norms currently being used are outd"
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    ABSTRACT: Head circumference growth in individuals with an Autism Spectrum Disorder (ASD) has been well characterized in the first two to three years of life and reflects a period of acceleration followed by a period of deceleration when compared with their typically developing (TD) peers. While this altered growth trajectory has been consistently found for head circumference, it is less clear if an abnormal growth trajectory also exists across measures of height and weight. Moreover, most studies have focused on infancy and early childhood, and no longitudinal data have been collected in older children with ASD. This review focuses on the physical growth trajectory of individuals with ASD, and proposes that a general growth dysregulation is present in ASD, and that an endophenotype within ASD may exist that is characteristic of extreme overgrowth. Two possible explanations for a general growth dysregulation are suggested: (1) a connective tissue disorder, which is frequently associated with increased height and disproportionate body ratios; and (2) a dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, which regulates growth hormones. The existence of a general growth dysregulation, and possible endophenotype, may serve as a potential biological marker in ASD.
    Developmental Review 02/2015; 36. DOI:10.1016/j.dr.2015.02.001 · 3.23 Impact Factor
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    • "Though it is currently debated (Raznahan et al., 2013), ASD has been assumed for long to be a condition characterized by an early altered brain growth (see Courchesne et al., 2005, for a review; see Constantino et al., 2010; Hazlett et al., 2005, for large retrospective works). At birth, the head circumference of ASD individuals has been found to be slightly reduced (Courchesne et al., 2003) or of normal size (Hazlett et al., 2005). "
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    ABSTRACT: Current evidence suggests the phenotype of Autism Spectrum Disorder to be driven by a complex interaction of genetic and environmental factors impacting onto brain maturation, synaptic function and cortical networks. However, findings are heterogeneous and the exact neurobiological pathways of Autism Spectrum Disorder still remain poorly understood. The co-twin control or twin-differences design is a potentially powerful tool to disentangle causal genetic and environmental contributions on neurodevelopment in Autism Spectrum Disorder. To this end, monozygotic twins discordant for this condition provide unique means for the maximum control of potentially confounding factors. Unfortunately, only few studies of a rather narrow scope, and limited sample size, have been conducted. In an attempt to highlight the great potential of combining the brain connectome approach with monozygotic twins design, we first give an overview of the existing neurobiological evidence for Autism Spectrum Disorder and its cognitive correlates. Then, a special focus is made onto the brain imaging findings reported within populations of monozygotic twins phenotypically discordant for Autism Spectrum Disorder. Finally, we introduce the brain connectome model and describe an ongoing project using this approach among the largest cohort of monozygotic twins discordant for Autism Spectrum Disorder ever recruited.
    Autism 04/2014; 19(5). DOI:10.1177/1362361314535510 · 3.50 Impact Factor
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    • "This is likely to be the result of the modest size of the high-risk sample in the current study (N = 44). Whilst recurrence rates approaching 30% have been found in other moderate size samples (e.g., Landa, Holman & Garrett-Mayer, 2007; Paul, Fuerst, Ramsay, Chawarska & Klin, 2011) these rates are sample specific and will likely not be generalizable as autism recurrence rates from larger samples converge between 10% and 20% (Constantino et al., 2010; Ozonoff et al., 1 Clinical judgement is considered more accurate than instrument thresholds (even on so-called 'gold standard' measures), in particular for young children (Charman & Baird, 2002). Our approach to diagnosis at 3 years is consistent with other published studies on highrisk siblings (Ozonoff et al., 2011; Zwaigenbaum et al., 2009) and is in line with the recommendations of the Baby Sibs Research Consortium of which we are members. "
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    ABSTRACT: Face recognition difficulties are frequently documented in children with autism spectrum disorders (ASD). It has been hypothesized that these difficulties result from a reduced interest in faces early in life, leading to decreased cortical specialization and atypical development of the neural circuitry for face processing. However, a recent study by our lab demonstrated that infants at increased familial risk for ASD, irrespective of their diagnostic status at 3 years, exhibit a clear orienting response to faces. The present study was conducted as a follow-up on the same cohort to investigate how measures of early engagement with faces relate to face-processing abilities later in life. We also investigated whether face recognition difficulties are specifically related to an ASD diagnosis, or whether they are present at a higher rate in all those at familial risk. At 3 years we found a reduced ability to recognize unfamiliar faces in the high-risk group that was not specific to those children who received an ASD diagnosis, consistent with face recognition difficulties being an endophenotype of the disorder. Furthermore, we found that longer looking at faces at 7 months was associated with poorer performance on the face recognition task at 3 years in the high-risk group. These findings suggest that longer looking at faces in infants at risk for ASD might reflect early face-processing difficulties and predicts difficulties with recognizing faces later in life.
    Developmental Science 12/2013; 17(4). DOI:10.1111/desc.12141 · 3.89 Impact Factor
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