A multicenter study on clinico-epidemiological profile of phenylketonuria in Egyptian children

Phenylketonuria is the most common heritable metabolic disorder. Early detection through newborn screening and proper nutritional management are essential for preventing neurodevelopmental complications. This study aims to describe the epidemiological profile of PKU in Egypt, assess the impact of early diagnosis, and examine the relationship between dietary adherence and comorbidities, including developmental and growth impairment. This is a multicenter retrospective cross-sectional study conducted in four university hospitals in Egypt between January 2024 and January 2025. A total of 365 patients with PKU aged 0-18 years were included. Data on demographics, phenotype classification, complications, and diet adherence were collected. We found that the most common PKU phenotype was classic PKU (36.3%). Early diagnosis through NBS was reported in 67.7%, and dietary adherence in 79.5%. Developmental delay was significantly lower in early-diagnosed children (3.2%) than in late-diagnosed children (100%). BH4 deficiency (1.6%) was associated with developmental delay and epilepsy despite early diagnosis. Diet adherence was linked to lower phenylalanine levels and fewer complications. Neurodevelopmental problems in PKU were decreased by the national NBS program. Better results depend on early diagnosis, diet adherence, and awareness of BH4 deficiency. Diet non-adherence not only worsens neurodevelopmental outcomes but also negatively affects growth parameters in these children.