Prevalence, Spectrum, and Management of Thyroid Dysfunction in Children with Down Syndrome: A Retrospective Study from Southern Saudi Arabia

<b>Background:</b> Down syndrome (DS) is strongly associated with a high prevalence of thyroid dysfunction. International guidelines recommend regular screening to ensure early detection and management. This study aimed to determine the prevalence, spectrum, and management outcomes of thyroid dysfunction in children with DS in the Aseer region of Saudi Arabia. <b>Methods:</b> A retrospective cross-sectional study was conducted by reviewing the medical records of 106 children with DS from two major healthcare centers: Abha Maternity and Children Hospital and King Khalid University Medical Center. Data on demographics, clinical symptoms, thyroid function tests, autoimmune status, treatment, and follow-up patterns were collected and analyzed. <b>Results:</b> The prevalence of thyroid dysfunction was 52.8%. Subclinical hypothyroidism was the most common disorder (46.4%), followed by autoimmune hypothyroidism (30.4%). Patients with thyroid dysfunction had a significantly higher symptom burden, particularly in metabolic, dermatological, and gastrointestinal domains (<i>p</i> < 0.01). A strong family history of thyroid disease was a significant risk factor (adjusted odds ratio (aOR) = 4.57, 95% CI: 1.89-11.6, <i>p</i> < 0.001). While adherence to screening and follow-up was high (78.0% and 82.1%, respectively), a critical gap was identified in treatment optimization, with 74.4% of patients treated potentially requiring levothyroxine dose adjustment. <b>Conclusions:</b> Thyroid dysfunction is highly prevalent in the Southern Saudi children with DS, with subclinical hypothyroidism and autoimmune hypothyroidism being the most common types. Despite good screening adherence, there is a substantial need for improved treatment titration and long-term management to optimize patient outcomes in this population.