Anatom3DPhenylketonuria (PKU)
Phenylketonuria · Fenylketonurie (PKU)
What it is
An inherited lack of the enzyme that breaks down phenylalanine; the newborn heel-prick test finds it, and a lifelong special diet prevents brain damage.
Symptoms & signs
- No signs at birth
- untreated: developmental delay and learning disability
- seizures
- musty smell
- pale skin and hair
- adults off the diet: poor concentration, low mood
🚩 Get help if…
- call 112 / 911 now Fits (seizures) in a child with PKU
- see a doctor soon Missed or abnormal newborn heel-prick result
- see a doctor soon Child falling behind in development or behaviour
- see a doctor soon Pregnancy or plans for it — diet control must start before conceiving
Where it strikes
Medical treatment
- Newborn screening
- low-phenylalanine diet with protein substitutes for life
- sapropterin (BH4) for responders
- pegvaliase for adults
- strict control before and during pregnancy
- sepiapterin (Sephience) — approved 2025 (EMA, FDA)
Natural & lifestyle
- Dietitian-planned diet
- avoid aspartame
Emerging & experimental
- Gene therapy
- engineered probiotics
Alternative, off-label & anecdotal
Approaches used outside the guidelines, with what their supporters report and what testing has found so far.
- Large neutral amino acids — reduce the phenylalanine reaching the brain; small trials early / small studies
- Glycomacropeptide foods — small trials, and they taste better early / small studies
- Herbal remedies — no effect on the enzyme anecdotal / traditional
ICD codes
- ICD-10 E70.0
- ICD-11 5C50.00 Classical phenylketonuria