Perfil epidemiológico e situação clínica dos fenilcetonúricos assistidos por um serviço de referência em triagem neonatal do Nordeste do Brasil

Abstract

Introduction: Phenylketonuria (PKU), primarily caused by mutations in the hepatic enzyme phenylalanine hydroxylase, is a rare genetic disease with autosomal recessive inheritance that affects protein metabolism. The disease is detected through the Newborn Screening Test, as recommended by the National Neonatal Screening Program, and its treatment is based on a protein-restricted diet supplemented with a phenylalanine-free metabolic formula, which must be followed throughout life. Early diagnosis and treatment prevent neurological and cognitive damage, with intellectual disability being the most severe symptom of PKU. Metabolic treatment in Brazil is provided free of charge according to the criteria established by the Clinical Protocol and Therapeutic Guidelines for PKU. The timeliness and continuity of treatment are determining factors in the prognosis of patients; gaps in this process can compromise its effectiveness. Studies have been conducted to characterize the profile of these patients aiming to improve multidisciplinary care and the implementation of public policies that ensure regular access to treatment. Objectives: To analyze the epidemiological profile and clinical status of phenylketonuria (PKU) patients assisted by a Neonatal Screening Reference Service (NSRS) in Northeast Brazil. Additionally, to examine associations between epidemiological, clinical, and treatment variables that influence the prognosis of these patients and to evaluate the outpatient multidisciplinary care provided by the NSRS and the logistical aspects of access to treatment within the state program from the patient's perspective. Methodology: This is a cross-sectional, observational, descriptive, and analytical study conducted through the administration of questionnaires, medical record analysis, and anthropometric assessment. Statistical analysis was performed using SPSS 26 software, and Pearson's Chi-squared test and Fisher's exact test were conducted when necessary. Results: A total of 39 phenylketonuria (PKU) patients were evaluated during the period from March 2022 to May 2023, covering 90.69% of the patients registered in the NSRS. 43.6% of the sample consisted of children, with 69.2% being male, and a prevalence of mild PKU (66.7%). Approximately 85% exhibited altered metabolic control, and 69.2% reported irregular therapeutic follow-up. The specialized multidisciplinary outpatient care received positive evaluations, while logistical gaps were identified. Significant statistical associations were observed between late diagnosis and symptomatic cases at diagnosis (p=0.04), the presence of clinical complications and irregular treatment (p=0.007), the presence of clinical complications and altered metabolic control (p=0.03), receipt of social benefits and cognitive impairment (p=0.002), altered metabolic control and irregular treatment (p=0.007), and negligence/dietary non-compliance and irregular treatment (p=0.02). Conclusion: A significant portion of phenylketonuria patients experiences poor metabolic control associated with logistical access gaps to recommended metabolic treatment, resulting in significant clinical and cognitive complications.