What is the latest nutritional treatment for phenylketonuria?

Phenylketonuria (PKU) is a rare hereditary condition in which the amino acid phenylalanine is not properly metabolized. PKU can cause severe mental retardation if not treated.

Phenylalanine is 1 of the 8 essential amino acids found in protein-containing foods. In PKU, phenylalanine cannot be used in a normal fashion because of the missing enzyme. Subsequently, high levels of phenylalanine, and 2 closely-related phenylalanine derivatives, build up in the body. These compounds are toxic to the central nervous system and cause brain damage.

Damage to the brain causes marked mental retardation by the end of the first year of life if the offending proteins are not scrupulously avoided. Older children may develop movement disorders (athetosis), rocking, and hyperactivity.

PKU is a treatable disease that can be easily detected by a simple blood test. Most states require a screening test for all newborns, generally done with a heelstick shortly after birth.

Because phenylalanine is involved indirectly in the production of melanin, the pigment responsible for skin and hair color, children with phenylketonuria often have lighter complexions than their unaffected siblings. There is a characteristic "mousy" odor that results from the accumulation of phenylacetic acid. This odor may be detected on the breath, skin, and urine if the condition has not been treated immediately from birth or if foods containing phenylalanine are consumed.

Treatment includes a diet that is extremely low in phenylalanine, particularly when the child is growing. Strict compliance to the diet is necessary to prevent or minimize mental retardation. This requires close supervision by a registered dietitian or physician, and cooperation of the parent and child.

Phenylalanine occurs in significant amounts in milk, eggs and other common foods. Nutrasweet (aspartame) also contains phenylalanine, and products containing aspartame should be avoided by children with this disorder. A special infant formula called Lofenalac is made for infants with PKU. It can be used throughout life as a protein source that is extremely low in phenylalanine and balanced for the remaining essential amino acids.

Adult women who have PKU and who plan to become pregnant should also adhere to a strict low-phenylalanine diet both before becoming pregnant and throughout the pregnancy.

I'm not sure about latest, things haven't changed too much regarding their diet, however, what the dieticians are trying now in australia is making fruits and vegetables that are 2 grams or less of protein free (not counted in the diet) more to promote healthy eating.
Also there is a drug (tablet, i think) that they are also testing. you take the tablet and it helps the body absorb the protein/phenylalanine much more quicker then what the phenylketonuric's body does naturally, So far its worked but there is a long process to be done with new drugs on the market and there's also governament funding etc.
I'm keeping a close eye on that one.