The Burden of Congenital Hypothyroidism Without Newborn Screening: Clinical and Cognitive Findings from a Multicenter Study in Algeria

Background: The absence of biochemical newborn screening (NBS) delays the diagnosis and treatment of congenital hypothyroidism (CH), resulting in irreversible neurodevelop-mental damage. To determine the age at diagnosis of CH in Algerian children and to de-scribe its clinical and biological characteristics, etiology, and outcome, we conducted a multicenter retrospective cohort study involving 288 children with CH across 20 pediatric centers between 2005 and 2023. The median age at diagnosis was 1.6 months, and only 28% of patients started treatment before 30 days. Prolonged neonatal jaundice was the most frequent presenting symptom (58%), severe CH (fT4 < 5 pmol/L) was observed in 35% and 52% received an insufficient initial dose of L-T4. The median IQ of the 47 patients tested was 86, 11% had an IQ <70 and a negative correlation was found between age at diagnosis and IQ (r = -0.48, p = 0.001). In children reassessed at age 3, 51% had normal thyroid function, indicating transient CH. Delayed diagnosis and suboptimal treatment of CH remain major challenges in Algeria, leading to substantial neurodevelopmental deficits and highlights the urgent need for implanting a national NBS. Pediatricians must remain cognizant of early clinical signs of CH to allow timely diagnosis and intervention.