A patient with phenylketonuria (PKU) or hyperphenylalaninemia may have a spectrum of neuropsychiatric changes. These may be especially pronounced in patients who go undiagnosed.
Variables affecting severity of neuropsychiatric manifestation:
(1) exposure to maternal PKU
(2) severity of PKU
(3) adherence to dietary restrictions
(4) other psychiatric disordersunrelated to PKU
Psychiatric manifestations:
(1) anxiety and panic attacks
(2) depression
(3) agoraphobia or other phobias
(4) self-harm
(5) mood swings
(6) agitation
(7) psychosis or schizophrenia
Neurological manifestations may include:
(1) spasticity
(2) tremor
(3) mental retardation or decreases in IQ
(4) executive function deficits
(5) brisk reflexes
(6) paralysis
(7) gait disorder
(8) seizures
(9) impaired memory
(10) attention deficit hyperactivity disorder (ADHD)
Manifestations may get worse during periods of dietary noncompliance and improve with compliance. A patient with worsening of psychiatric or neurologic features should have the blood phenylalanine concentrations determined.
