Benign hyperphenylalaninemia

Overview

Phenylalanine is an essential amino acid, one of the building blocks of protein that we need in our diets. Extra phenylalanine that we eat or drink is normally broken down by a specific enzyme and its cofactor.

Causes

PKU is an inherited condition, passed along as a recessive trait. There are over 100 different variations of the gene that can result in PKU. When both parents are carriers, about one in four of their children will have the disease. Babies with classic PKU are often the blondest children in the family. They are typically blue-eyed, fair-skinned babies.

Prevention

PKU is not a preventable disease, though the damage of PKU can usually be prevented by early identification and treatment. In addition to newborn screening, prenatal testing and carrier testing are possible.

Diagnosis

PKU is an inherited condition, passed along as a recessive trait. There are over 100 different variations of the gene that can result in PKU. When both parents are carriers, about one in four of their children will have the disease. Babies with classic PKU are often the blondest children in the family. They are typically blue-eyed, fair-skinned babies.

Treatment

Classic PKU is treated with a careful, strict low-phenylalanine diet. Because phenylalanine is an essential amino acid, it must not be eliminated from the diet – only decreased. Careful balancing, frequent monitoring, and close supervision are important. Low phenylalanine formulas are available.