Patient's question:
Patient Gender: Male Age: Half a year Main Symptoms: Intellectual disability, convulsions during fever, unclear speech. Onset Time: 1.5 years Test Results: Mild ketonuria detected in urine test.Doctor's answer:
1. Low-phenylalanine diet is mainly applicable to patients with typical PKU and those with persistently elevated plasma phenylalanine levels above 1.22 mmol/L (20 mg/dL). Since phenylalanine is an essential amino acid for protein synthesis, complete deficiency can also lead to neurological damage. Therefore, infants can be fed specialized low-phenylalanine formula milk, and when introducing complementary foods during the toddler stage, low-protein foods such as starches, vegetables, and fruits should be prioritized.The required phenylalanine intake is approximately:
- For infants under 2 months: 50–70 mg/(kg·d)
- For infants aged 3–6 months: 40 mg/(kg·d)
- For children aged 2 years: 25–30 mg/(kg·d)
- For children over 4 years: 10–30 mg/(kg·d)
The goal is to maintain plasma phenylalanine levels between 0.12–0.6 mmol/L (2–10 mg/dL). Dietary control should be maintained at least until after puberty.
Children's Hospital, the Institute of Child Health, and the Maternity Hospital in Beijing should be able to conduct these tests. Once diagnosed, the first step is to provide a low-phenylalanine diet and symptomatic treatment.