PKU

This is a Wiki explanation:


Phenylketonuria (PKU) is an autosomal recessive genetic disorder characterized by a deficiency in the hepatic enzyme phenylalanine hydroxylase (PAH). This enzyme is necessary to metabolize the amino acid phenylalanine ('Phe') to the amino acid tyrosine. When PAH is deficient, phenylalanine accumulates and is converted into phenylpyruvate (also known as phenylketone), which is detected in the urine.
Since its discovery, there have been many advances in its treatment. It can now be managed by the patient with little or no side-effects, just the inconvenience of managing the treatment. If, however, the condition is left untreated, it can cause problems with brain development, leading to progressive mental retardation, brain damage, and seizures. In the past, PKU was treated with a low-phenylalanine diet. Latter-day research now has shown that diet alone may not be enough to prevent the negative effects of phenylalanine levels. Optimal treatment involves lowering blood Phe levels to a safe range and monitoring diet and cognitive development. Lowering of phenylalanine levels to a safe range may be achieved by combining a low-phenylalanine diet with protein supplements. There is currently no cure for this disease; however, some treatments are available with varying success rates. In general, PKU is detected through newborn screening and diagnosed by a geneticist. PKU clinics around the world provide care for PKU patients to optimize phe levels, dietary intake, and cognitive outcomes.