Pre-schoolchildren with autism spectrum disorders are rarely macrocephalic: a population study

Numerous clinical studies over the past decades have concluded that there is an association between autism spectrum disorders (ASD) and large head size. Lately, some studies have reported conflicting results. The present study was conducted with a view to assess the presence of macrocephaly in a community-representative group of pre-school children with ASD. The prevalence of ASD in this general population was 0.8%. Thirty-three children (5 girls, 28 boys) recruited after general population screening for ASD, and diagnosed with ASD (two-thirds not globally delayed) were assessed as regards growth parameters; height, weight, and head circumference (HC), at birth and at comprehensive medical-psychiatric diagnostic examinations at a mean age of 3 years. Macrocephaly in the present study was defined as HC above the 97th percentile, and ≥ 2 SD above recorded length/height. Only one of the 33 children (3%) had macrocephaly which is similar to the general population prevalence. Another 9% had a big but proportional head. None of the children were microcephalic. In this community-based study we found no evidence to support a strong link between a large head size and ASD. Conclusions must be guarded because of the relatively small number of ASD cases included.