Bone Mineral Density in Adults With Hyperphenylalaninemia

Hyperphenylalaninemia (HPA) is a rare metabolic disorder caused by a deficiency of the enzyme phenylalanine hydroxylase (PAH). Elevated plasma levels of phenylalanine (phe) cause mental retardation, microcephaly, delayed speech, seizures, eczema, and behavior problems. Adequate control of the plasma levels of phe by a phe-restricted diet can prevent the developmental and behavioral problems.

The foundation of this diet is a phe-free medical product/formula made from free amino acids. Based on longitudinal studies, it has been reported that the most benefit is attained by individuals who maintain a phe-restricted diet throughout life. Despite the obvious benefits of the diet, it has been suggested that the dietary restrictions may be associated with poor bone health in these patients. However, data supporting this has been reported in studies with small sample sizes and/or inadequate sample populations that include children. There is a paucity of data on bone health in adults with HPA.

The investigators propose an observational study to describe the bone health status among adults with a diagnosis of HPA and to compare them to established normative age and gender-specific values among healthy individuals. The investigators hypothesize that adults with HPA will have lower bone density as measured by a dual x-ray absorptiometry (DXA) scan compared to the established normative values.

Study Overview

• Status: Completed
• Conditions: Phenylketonurias

• Study Type: Observational
• Enrollment (Actual): 28

Contacts and Locations

Study Locations

• United States
  • Texas
    • Houston, Texas, United States, 77030
      • University of Texas Health Science Center at Houston

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Adults with PKU or benign HPA followed at The University of Texas Health Science Center at Houston will be invited to participate in the study. In addition, adults with PKU or benign HPA in the State of Texas will be invited to participate.

Description

Inclusion Criteria:

• Diagnosis of HPA at birth
• Aged 18 or older

Exclusion Criteria:

• Peri-menopausal women
• Menopausal women
• Patients taking bisphosphonates
• Pregnant women
• Women who have been pregnant within one year of study enrollment
• Women who have breastfed within one year of study enrollment

Study Plan

How is the study designed?

Collaborators and Investigators

• Sponsor: The University of Texas Health Science Center, Houston
• Collaborators: BioMarin Pharmaceutical
• Investigators: Principal Investigator: Heather W Saavedra, MS, The University of Texas Health Science Center, Houston

Study record dates

Study Major Dates

• Study Start: September 1, 2010
• Primary Completion (ACTUAL): October 1, 2012
• Study Completion (ACTUAL): October 1, 2012

Study Registration Dates

• First Submitted: September 24, 2010
• First Submitted That Met QC Criteria: September 24, 2010
• First Posted (ESTIMATE): September 27, 2010

Study Record Updates

• Last Update Posted (ESTIMATE): June 12, 2015
• Last Update Submitted That Met QC Criteria: June 11, 2015
• Last Verified: June 1, 2015

More Information

Terms related to this study

• Keywords: Adults; Bone Mineral Density
• Additional Relevant MeSH Terms: Metabolic Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Genetic Diseases, Inborn; Metabolism, Inborn Errors; Brain Diseases, Metabolic; Brain Diseases, Metabolic, Inborn; Amino Acid Metabolism, Inborn Errors; Phenylketonurias
• Other Study ID Numbers: HSC-MS-10-0262