Early Generalized Overgrowth in Boys With Autism

Abstract

Context Multiple studies have reported an overgrowth in head circumference (HC) in the first year of life in autism. However, it is unclear whether this phenomenon is independent of overall body growth and whether it is associated with specific social or cognitive features. Objectives To examine the trajectory of early HC growth in autism compared with control groups; to assess whether HC growth in autism is independent of height and weight growth during infancy; and to examine HC growth from birth to 24 months in relationship to social, verbal, cognitive, and adaptive functioning levels. Design Retrospective study. Setting A specialized university-based clinic. Participants Boys diagnosed as having autistic disorder (n=64), pervasive developmental disorder–not otherwise specified (n=34), global developmental delay (n=13), and other developmental problems (n=18) and typically developing boys (n=55). Main Outcome Measures Age-related changes in HC, height, and weight between birth and age 24 months; measures of social, verbal, and cognitive functioning at age 2 years. Results Compared with typically developing controls, boys with autism were significantly longer by age 4.8 months, had a larger HC by age 9.5 months, and weighed more by age 11.4 months (P=.05 for all). None of the other clinical groups showed a similar overgrowth pattern. Boys with autism who were in the top 10% of overall physical size in infancy exhibited greater severity of social deficits (P=.009) and lower adaptive functioning (P=.03). Conclusions Boys with autism experienced accelerated HC growth in the first year of life. However, this phenomenon reflected a generalized process affecting other morphologic features, including height and weight. The study highlights the importance of studying factors that influence not only neuronal development but also skeletal growth in autism.

Very Low Birth Weight, Infant Growth, and Autism-Spectrum Traits in Adulthood

“…31 In contrast, studies not focusing on individuals born preterm show harmful effects of faster infant growth, including increased risk for an ASD diagnosis. [27][28][29][30] The discrepancy implies that the underlying mechanisms of ASD and ASD-related traits may depend on prematurity.…”

“…This enabled us to examine the associations between early postnatal growth and ASD-related traits in adulthood, whereas earlier research on growth and ASD has been conducted almost exclusively among children. [27][28][29][30][31] This also enabled us to make adjustments for psychiatric symptomatology that often accompanies ASD-related traits, namely attention-deficit/hyperactivity and anxiety problems. 52,53 Among individuals born preterm, the risk for higher levels of autism-spectrum traits, particularly those related to skills and preferences in social interaction, may persist into young adulthood.…”

“…25,26 By contrast, the existing data from studies focusing on infants born at term suggest that ASD is rather predicted by faster growth in head circumference, 27 length, and weight [28][29][30] during the first year of life. However, the 1 study that tested this association specifically in preterm children was not consistent with this.…”

A Hypothesis of Autism Approached with the Nonlinear Model

“…In these areas the neurons would be repeatedly stimulated because of the information gotten by the sensory organs of patients which would lead to overgrowth of brain [5][6][7].…”

A review of physical growth in children and adolescents with Autism Spectrum Disorder

“…Numerous brain imaging, HC, and post-mortem studies confirm an altered growth trajectory in ASD (Amaral, Schumann, & Nordahl, 2008;Redcay & Courchesne, 2005). The vast majority of studies suggest that HC, a viable measure of brain volume (Bartholomeusz, Courchesne, & Karns, 2002), is similar in both ASD and typically developing (TD) children when measured prenatally (Whitehouse, Hickey, Stanley, Newnham, & Pennell, 2011) and is either similar (Chawarska et al, 2011;Fukumoto et al, 2008;Gillberg, 2002;Webb et al, 2007;Whitehouse et al, 2011) or slightly smaller (Courchesne, Carper, & Akshoomoff, 2003;Dissanayake, Bui, Huggins, & Loesch, 2006;Mraz, Green, Dumont-Mathieu, Makin, & Fein, 2007) at birth than in TD children.…”