Association between craniofacial anomalies, intellectual disability and autism spectrum disorder : Western Australian population-based study

Background: Accurate knowledge of the relationship between craniofacial anomalies (CFA), intellectual disability (ID) and autism spectrum disorder (ASD) is essential to improve services and outcomes. The aim is to describe the association between CFA, ID and ASD using linked population data. Methods: All births (1983-2005; n = 566,225) including CFA births (comprising orofacial clefts, craniosynostosis, craniofacial microsomia and mandibulofacial dysostosis) surviving to 5 years were identified from the birth, death, birth defects and midwives population data sets. Linked data from these data sets were followed for a minimum of 5 years from birth until 2010 in the intellectual disability database to identify ID and ASD. These associations were examined using a modified Poisson regression. Results: Prevalence of ID and ASD was higher among CFA (especially with additional anomalies) than those without [prevalence ratio 5.27, 95% CI 4.44, 6.25]. It was higher among CFA than those with other gastrointestinal and urogenital anomalies but lower than nervous system and chromosomal anomalies. Children with CFA and severe ID had a higher proportion of nervous system anomalies. Conclusions: Findings indicate increased ID and ASD among CFA but lower than nervous system and chromosomal anomalies. This population evidence can improve early identification of ID/ASD among CFA and support service planning. Impact: Our study found about one in ten children born with craniofacial anomalies (CFA) are later identified with intellectual disability (ID).Prevalence of ID among CFA was higher than those with other gastrointestinal, urogenital, and musculoskeletal birth defects but lower than those with the nervous system and chromosomal abnormalities.Most children with craniofacial anomalies have a mild-to-moderate intellectual disability with an unknown aetiology.On average, intellectual disability is identified 2 years later for children born with non-syndromic craniofacial anomalies than those with syndromic conditions.Our findings can improve the early identification of ID/ASD among CFA and support service planning.