The association of neurofibromatosis and autism symptomatology is confounded by behavioral problems

Aim: to evaluate if autism symptoms and diagnoses are raised in children with neurofibromatosis type 1 (NF1), to which levels, and to determine if co-occurring symptomatology accounts for this elevation. Method: We interrogated our hospital electronic medical records. We collected parental reports of autism symptomatology, adaptive behavior, and co-occurring behavioral and emotional problems on a subsample of 45 children (9 years 2 months, 49% male). Age- and sex-matched controls with (N=180) or without ASD (N=180) were drawn from the Simons Simplex Collection and compared cross-sectionally to participants with NF1. Results Diagnoses of ADHD (8.8%), not of ASD (2.1%), were raised among 968 children with NF1 identified through electronic search. Mean Social Responsiveness Score (55.9) was below the cut-off of 60 for significant autism symptoms. Participants with NF1 had significantly more autism and behavioral symptoms than typically developing (TD) controls, and significantly less than controls with autism, with one exception: ADHD symptom levels were similar to those of autistic controls. When emotional, ADHD, and communication scores were covaried, the difference between participants with NF1 and TD controls disappeared almost entirely. Interpretation: Our results do not support an association between NF1 and autism, both at the symptom and disorder levels.