Tirzepatide for weight and behavior management in a patient with Smith-Magenis syndrome.

Smith-Magenis syndrome (SMS) is a rare neurodevelopmental disorder characterized by intellectual disability, behavioral dysregulation, and hyperphagia-driven obesity. While dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists have demonstrated efficacy in the general population, their use in patients with SMS has not been described. We report the case of a 31-year-old woman with SMS (17p11.2 deletion) treated with tirzepatide, a dual GIP/GLP-1 receptor agonist. The patient presented with lifelong obesity (body mass index [BMI] 32.0-32.9 kg/m2 in adulthood) and aggressive behaviors refractory to standard management. Following initiation of tirzepatide, titrated to 5 mg weekly, she achieved 9.4% weight loss (7.3 kg) over 10 months, along with improvement in fasting glucose levels. Concurrently, caregivers reported notable behavioral improvements, including reduced food-seeking behavior and impulsivity. Quantitative analysis demonstrated a significant reduction in aggression. The treatment was well tolerated. This case suggests that tirzepatide may represent a promising therapeutic option for SMS, targeting both metabolic and central nervous system pathways involved in its phenotype.