Autism Spectrum Disorder in Hypothalamic Hamartoma: Early Developmental Trajectory, Symptom Profile, and Relevance for Autism Research

Focal brain lesions occurring during critical developmental periods can shed light on the neural substrates underlying autistic symptoms. Hypothalamic hamartomas (HH) are rare congenital malformations that are typically characterized by pharmacoresistant epilepsy, endocrine disturbances, and behavioral or psychiatric disorders. Although autistic symptoms have occasionally been reported in children with HH, they remain poorly described and are rarely documented with standardized diagnostic tools. We present a case report of a 3‐year‐old boy with HH who was followed from 2 years of age. The report combines detailed early neurodevelopmental history, neuroimaging data, and standardized autism assessments. The child exhibited global developmental delay, early intense sensory features, and marked social communication deficits. The first developmental difficulties preceded the onset of seizures. At 29 months of age, magnetic resonance imaging identified a small intrahypothalamic hamartoma. At 36 months, the Autism Diagnostic Observation Schedule‐2 and the Autism Diagnostic Interview‐Revised confirmed the diagnosis of autism spectrum disorder (ASD). A comparison with 3 subjects with ASD matched for sex, chronological age, and developmental age showed that the child presented less severe deficits in sharing enjoyment and less intense unusual preoccupations than age‐matched autistic peers. This case highlights the importance of systematic ASD screening in children with HH, allowing timely referral to evidence‐based early interventions. Moreover, HH may offer a valuable framework for investigating early neurodevelopmental mechanisms associated with ASD, while highlighting the potential contribution of the hypothalamus to early autism mechanisms.