High prevalence of overweight and obesity in females with phenylketonuria

The primary treatment for phenylketonuria (PKU) is a low phenylalanine diet together with an amino acid-based, phenylalanine-free formula. Thus, PKU patients tend to consume a diet enriched in carbohydrates which could predispose to obesity. Studies in the 1980s and 1990s demonstrated that school-age phenylketonuria (PKU) patients have a higher mean body weight compared to a control population. However, no recent studies in the United States PKU population have examined whether this trend has persisted or whether adolescents are also affected. To investigate whether pediatric PKU populations (ages 2-20years) in two major metropolitan areas of the United States (Cleveland, OH and Houston, TX) have a higher than expected percentage of overweight (BMI≥85th percentile) relative to the general population in the United States (NHANES), a retrospective chart review of PKU patients born between 1990 and 2008 and followed in Cleveland, OH (Rainbow Babies and Children's Hospital/University Hospitals Case Medical Center) and in Houston, TX (Texas Children's Hospital) was performed. Based on data from the U.S., 40% of pediatric PKU patients were overweight or obese. However, the percentage of overweight females (55%) and obese females (33%) is 1.8× and 2.1× higher respectively than expected based on comparison data from U.S. children. Further studies are necessary to identify potential strategies for prevention of excessive weight gain in children with PKU, especially in females.