Phenylketonuria is an inherited disease inherited as an autosomal recessive disease, so both mother and father must be carriers of this disease in order for the disease to occur. Due to the high rates of consanguineous marriage in our country, it is seen at a higher rate than European countries and America. In our country, approximately 300 babies with phenylketonuria are born every year and the incidence is calculated as one in 3,000 – 4,000 newborns.
What is phenylketonuria disease?
The disease is caused by a defect in phenylalanine metabolism. Phenylalanine is an amino acid, a protein building block that is essential for our body and needs to be taken with nutrients. While this amino acid must be converted into tyrosine with the enzyme phenylalanine hydroxylase in our body and perform its necessary functions in this way, as a result of an error in this cycle, the level of phenylalanine in the blood increases and phenylketonuria occurs.
Diseased babies are healthy at birth. With the increase of phenylalanine level in the blood, phenylalanine crosses the blood brain barrier and causes impaired brain development and neurological damage. If these babies are not diagnosed and treated in the early period, irreversible brain damage, mental retardation, growth retardation, seizures, involuntary contractions, gait disorders, hyperactivity, self-harm, autistic behavioral disorders are seen. The urine of these children is malodorous due to phenylalanine metabolites, and this smell is likened to the smell of mouse urine. Untreated children with phenylketonuria gradually decrease pigmentation in the hair, skin and eyes, and these children become blond, fine-haired and blue-eyed.
How is the disease diagnosed?
The diagnosis of the disease is made easily by determining the increase in blood phenylalanine level in newborn screening tests. For this reason, before the baby is discharged from the hospital, a few drops of blood are taken from the heels of the newborn babies on special papers called Guthrie cards in our country. In order for the Guthrie test not to give a false negative result, the blood sample should be taken after the first 24 hours of life following the baby’s adequate protein intake. In babies who will be discharged before the first 24 hours, a new blood sample should be taken within the first week after the first blood sample.
How is the disease treated?
The most important point of treatment is to identify these children in the early period and to give a diet restricted to phenylalanine starting from the first days of life.
Can phenylketonuria patients be breastfed?
These babies can be breastfed by using medical formula without phenylalanine together with breast milk and by closely monitoring their blood phenylalanine levels.
What are the products that patients with phenylketonuria should not consume?
- Foods made from milk and dairy products
- Meat and meat products (red meat, chicken, fish, turkey meat, salami, sausage,
- soudjouk, bacon, roasting, shellfish, mussels etc.)
- Internal organs of the animal (brain, liver, kidney, etc.)
- Normal bread (wheat, rye, oats, corn breads)
- Dried nuts (hazelnuts, peanuts, chickpeas, seed varieties, almonds, walnuts)
- Dry legumes (dried beans, chickpeas, lentils, broad beans, soybeans, dried kidney beans)
- Ready food (crackers, biscuits, cakes, cookies, cakes and all foods made with prohibitions)
- All beverages, chewing gum, foods containing aspartame and phenylalanine.
Is it possible to prevent the disease?
Since it is an inherited disease, it is not possible to prevent it, but with treatment, neurological sequelae can be prevented and a healthy life can be sustained.