Microcephaly in preschool children with Autism Spectrum Disorder

Background: The present study presents results of head circumference (HC) measurements in a group of children being part of a larger group of children referred for neuropsychiatric assessment to a neuropsychiatric assessment team in Sweden. Methods: Of the 126 children included in the present study HC was possible to measure in 114 individuals. However, two of these children were not diagnosed since they did not conclude the study, leaving 112 children for further assessment. In addition, birth data was recovered either from the digital birth sheet used in Sweden for the registration of birth data, or in a few cases from the Child Care Centers or medical journals if the child had been admitted to hospital care after birth. Results: Of the 112 individuals, only one individual, a boy, diagnosed with ICD-10 Autism, had a HC above the 97.5th percentile at birth. At the physical assessment included in the study one individual, a boy (not the same boy as mentioned above) was found to have a HC above the 97.5th percentile. Hence, 1.2 % of the boys in this study with an ICD-10 ASD diagnosis were macrocephalic. In contrast, 6.7 % of the boys, and 8% of the girls, who received an ICD-10 ASD diagnosis had a HC below the 2.5th percentile and were considered microcephalic at the assessment. Conclusions: The results from this study could not confirm previous research arguing macrocephaly to be considerably more common in ASD than in the general population. However, in contrast, the results from this study indicated that microcephaly could be more common in children with ICD-10 ASD, for both sexes, than in the general population. Since none of the children had been microcephalic at birth the results indicate a relative decrease in HC over time in these individuals.