NICHD Phenylketonuria (PKU) Research Information

Since its establishment, NICHD has played a major role in PKU-related research. In the 1960s, federally supported researchers demonstrated the safety and effectiveness of a PKU screening test for newborns that allowed the condition to be detected and diagnosed early, before any adverse effects occurred. Later, NICHD supported research on the safety and efficacy of a phenylalanine-restricted diet for those with PKU to prevent intellectual and developmental disabilities (IDDs) from the condition. As a result, PKU has been nearly eliminated as a cause of IDDs in the United States.

The institute’s portfolio covers a variety of topics related to PKU, including pathophysiology (the functional changes that accompany the disorder), genetics, treatment interventions, pregnancy in women with PKU, and strategies for lifelong management of the disorder. NICHD also supports research to improve newborn screening technology for PKU (and other conditions) and to expand researchers’ access to screening data.

NICHD supports and conducts research on a wide range of topics related to PKU and other metabolic disorders. Research areas include newborn screening, healthy fetal development in pregnant people with PKU, and the pathophysiology of PKU-related IDDs. Key NICHD research issues include the following:

  • Newborn screening: Efforts focus on making improvements to screening technology, supporting longitudinal research on the health of children identified through screening, and expanding access to screening data for translational research.
  • Therapeutic interventions: Researchers are currently investigating the use of gene therapy interventions. Other interventions, such as lifelong dietary treatment, have been studied in the past and continue to be of interest.
  • Psychosocial issues: Researchers have developed multiple studies in this area. Recently, they explored issues such as family adaptation to a PKU diagnosis.
  • Pathophysiology: Scientists are exploring processes and metabolism as they relate to brain functioning in PKU and other disorders.

NICHD’s PKU-related portfolio is maintained largely through the Intellectual and Developmental Disabilities Branch (IDDB). The institute supports diverse projects, including research on pregnancy and PKU, gene therapy, improved screening, and pathophysiology of the disorder.

Institute Activities and Advances

Since its establishment, NICHD has played a major role in PKU-related research. In the 1960s, researchers supported by the federal Children’s Bureau demonstrated the effectiveness of a PKU screening test that could easily and inexpensively screen for the disorder on a mass basis. Soon after, NICHD led research on the safety and effectiveness of a restricted diet to treat PKU among newborns who had been identified using the screening test. As a result of the test and the institute’s follow-up research, PKU has been nearly eliminated as a cause of IDDs in the United States.

NICHD continues to address newborn screening for PKU and other disorders through the Hunter Kelly Newborn Screening Research Program. The program is authorized to conduct, coordinate, and expand research in a number of screening-related areas. The topics of study include:

  • Identifying new screening methods and technologies
  • Educating the workforce of health care providers about screening
  • Developing and implementing information systems for parents and providers
  • Establishing a network of state programs for screening newborns

Other NICHD projects look at the psychosocial aspects of screening, such as how family members respond to, share, and use information gained when a newborn is diagnosed.

NICHD-supported researchers have also explored other issues central to understanding PKU and improving the lives of people who live with the disorder. One particularly significant focus has been maternal PKU. A collaborative study of women with PKU, initiated by NICHD, found that women who followed a low-phenylalanine diet before and during pregnancy prevented IDDs in their offspring. The largest and most definitive clinical study of maternal PKU to date, the project also demonstrated the efficacy of dietary treatment in reducing the incidence of microcephaly, intrauterine growth retardation, and congenital heart disease among offspring.

Other NICHD research focuses on aspects of PKU dietary treatments. For example, NICHD-supported researchers found that adults and adolescents on a PKU diet often had low blood levels of important fatty acids. As a result, the researchers recommended adding supplements that provided key fatty acids as appropriate for patients.

NICHD-supported research also explores emerging treatments for PKU, such as gene therapy. For example, some researchers are studying mice to better understand the expression of the phenylalanine metabolizing system in muscles.

Other Activities and Advances

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