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 a urine test.Doctor's answer:
1. Low-phenylalanine diets are primarily suitable for patients with classic PKU and those with persistently elevated 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 specially formulated low-phenylalanine formula milk, and when introducing complementary foods during the toddler stage, it is recommended to focus on low-protein foods such as starches, vegetables, and fruits.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 blood phenylalanine levels within the range of 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 are capable of performing these tests. Once diagnosed, the first step is to provide a low-phenylalanine diet and symptomatic treatment.