Evaluation of babies with hyperphenylalaninemia diagnosed in the National Newborn Screening Program in Istanbul in 2019

INTRODUCTION: To evaluate the 2-year follow-up of hyperphenylalaninemia (HPA) patients born in 2019.
METHODS: Growth, neuromotor development, and vitamin levels of 61 two-year-old babies followed up with the diagnosis of HPA in 2019 were evaluated.
RESULTS: Thirty-six (59.02%) of the cases were female. The mean birth weight of the babies was 3198.7±504 g and 23.1% (n=14) of them were preterm. The mean of initial National Newborn Screening Program phenylalanine (phe) levels was 3.85±1.86 mg/dL. The mean day to diagnosis was 13.29 days (range 4-18). Forty-eight (78.7%) of the patients declared sufficient knowledge about HPA follow-up. Follow-up compliance of the families was 67%. Among the infants who participated in our study, 4 (6.6%) patients were diagnosed with sapropterin dihydrochloride (BH4) responsive mild phenylketonuria (MPKU). No patient was started on with phe-restricted diet therapy. The remaining 32 (52.4%) infants were followed up with the diagnosis of female HPA. The follow-up of 25 (41%) male infants was terminated. Anemia was found in 4 (6.6%) babies. Iron deficiency in 4 (6.6%) and B12 deficiency in 9 (14.8%) babies were detected. There was no significant difference between MPKU and HPA groups regarding growth parameters and vitamin levels.
DISCUSSION AND CONCLUSION: No growth or neuromotor retardation was found in HPA patients. Vitamin D and, less frequently, vitamin B12 deficiencies are prominent. No difference was observed between the patients who passed from HPA to MPKU and HPA cases, in terms of growth, development, and nutritional status.