Untreated PKU can lead to: Irreversible brain damage and
marked intellectual disability
beginning within the first few months of life. Neurological problems such as seizures and tremors.
How does PKU affect intellectual development?
Phenylketonuria (PKU) is known to have a devastating effect on intellectual development early in life resulting in an IQ of
severe behavior problems
and severe epilepsy if treatment is not started soon after birth.
What is unique about the intellectual disability caused by PKU?
Intellectual disability in PKU is a
direct result of elevated levels of phenylalanine in the brain
which causes the destruction of the fatty covering (myelin) of individual nerve fibers. It can also cause depression by reducing brain levels of dopamine and serotonin (neurotransmitters).
Why do children with PKU develop intellectual disability?
Phenylalanine is a building block of proteins (an amino acid ) that is obtained through the diet. It is found in all proteins and in some artificial sweeteners.
If PKU is not treated, phenylalanine can build up to harmful levels in the body
, causing intellectual disability and other serious health problems.
Why does PKU cause mental retardation?
A Gene Causing Mental Retardation
PKU is usually caused by
deficiency of phenylalanine hydroxylase
, which metabolizes the amino acid phenylalanine. It is also more rarely caused by deficiencies of enzymes that synthesize the main cofactor that this enzyme needs to function.
What is the life expectancy of someone with PKU?
PKU does not shorten life expectancy
, with or without treatment. Newborn screening for PKU is required in all 50 states. PKU is usually identified by newborn screening. A child's outlook is very good if she strictly follows the diet.
How does phenylalanine affect the brain?
The high plasma phenylalanine concentrations
increase phenylalanine entry into brain and restrict the entry of
other large neutral amino acids. In the literature, emphasis has been on high brain phenylalanine as the pathological substrate that causes mental retardation.
How does PKU affect the brain?
PKU affects the brain.
High blood Phe levels can cause disruptions in neurotransmitters like serotonin and dopamine, which are important for mood, learning, memory, and motivation. In addition to disrupting neurotransmitter balance, Phe itself can be directly
toxic
to the brain.
Does PKU affect memory?
AwPKU were
significantly impaired
compared to controls in most cognitive domains with the exception of inhibitory control and memory and learning. The impairment in visuomotor coordination was particularly severe.
As children and adolescents, patients with PKU may have
learning difficulties, school problems, decreased motivation, less social competence
, irritability, hyperactivity, mood disorders, and poor self esteem.
Which teaching is most important for a child with PKU?
Children and adults with PKU should eat
a low-protein diet
. They should avoid high-protein foods, like milk, dairy, meats, eggs, nuts, soy, and beans. A person with PKU also should avoid the artificial sweetener aspartame, which contains phenylalanine.
Can you outgrow PKU?
A person with
PKU does not outgrow it
and must stay on the diet for life.
What can a child with PKU eat?
When your baby is ready to eat solid foods, they can eat vegetables, fruits, some grains (like low-protein cereals, breads and pasta) and other low-phenylalanine foods. If your baby has PKU, they should not eat:
Milk, cheese, ice cream and other dairy products
.
Eggs
.
What does PKU smell like?
If PKU is untreated, or if foods containing phenylalanine are eaten, the breath, skin, ear wax, and urine may have a
“mousy” or “musty” odor
. This odor is due to a buildup of phenylalanine substances in the body.
Can a baby with PKU breastfeed?
This study provides further evidence that
mothers of infants with PKU can successfully breastfeed
, allowing exposure to the benefits of breastmilk and, in many cases, breastfeeding.
Is PKU more common in males or females?
Each year 10,000 to 15,000 babies are born with the disease in the United States and Phenylketonuria occurs
in both males and females of all ethnic backgrounds
(although it is more common in individuals of Northern European and Native American heritage.)
