Phenylketonuria and dentistry: review of the literature

Department of Pediatric Dentistry
St Joseph Hospital

Resident’s Name: Craig Elice Date: June 5, 2009
Article title: Phenylketonuria and dentistry: review of the literature
Author(s): Walker, JD, Cral JJ, McDonnell
Journal: J Dent. Child
Month, Year: July-August 1982
What is it? PKU is an autosomal recessive disorder noted by a defect in phenylalanine hydroxylase. This enzyme converts phenylalanine into tyrosine, which when defective accumulates in body fluids and causes brain damage and mental retardation.
Epidemiology: affects 1 in 15,000-18,000 births, showing a greater frequency in Irish and Scottish, and generally Caucasians.
Signs and Symptoms: Untreated PKU patients classically show moderate to severe mental retardation with schizoid behavior, hyperkinetic movements, microcephaly and are prone to seizures. The children are blonder then unaffected siblings, have blue eyes, a musty odor, and a tendency to have eczema.
Diagnosis: Early detection of neonates is performed by a bacterial inhibition assay to detect elevated phenylalanine in the serum. A diagnosis is made by having two serum phenylalanine levels greater than 20mg percent at least 24 hours apart while the infant is on a regular diet, Tyrosine levels of less than 5 mg percent, and a pattern of urinary metabolites.
Treatment: Dietary therapy should begin as early as possible. Products like Lofenalac or other low phenylalanine products are given to infants. The diet should be maintained to a minimum of 6 years of age when the brain is almost fully developed. However, continuation of the diet to a later age shows improved behavior and reduction in the severity of the eczema. No special considerations are necessary when treating the oral health of patients diagnosed with PKU