Can sapropterin help phenylketonuria pku newborns?

Can sapropterin help phenylketonuria newborns

Sapropterin is a synthetic form of tetrahydrobiopterin (BH4) that helps some newborns with phenylketonuria (PKU) process phenylalanine. It works by activating residual phenylalanine hydroxylase (PAH) enzyme activity in patients who respond to BH4.

What makes a newborn a sapropterin responder

Only about 20–30% of PKU patients respond to sapropterin. Responders show a 20–30% drop in blood phenylalanine levels after a short BH4 loading test. Genetic testing can also predict response based on residual PAH activity.

How does sapropterin work in newborns

The drug increases the co-factor availability for the PAH enzyme. When applied early in life, it often allows reduced dietary phenylalanine restrictions while maintaining safe blood levels. This can eroding the strictness of the special formula diet required for non-responders.

Does it work for classical PKU

It does not work for classical PKU cases caused by two severe PAH mutations. Those patients must still rely on protein-restricted diets and formula.<|eos|>