Phenylketonuria Scientific Review Conference: state of the science and future research needs

New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 μmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 μmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.

Parental permission for pilot newborn screening research: guidelines from the NBSTRN

There is broad recognition of the need for population-based research to assess the safety and efficacy of newborn screening (NBS) for conditions that are not on current panels. However, prospective population-based research poses significant ethical, regulatory, and logistical challenges. In the context of NBS, there have been a variety of approaches that address parental decision-making in pilot studies of new screening tests or conditions. This article presents an ethical and legal analysis of the role of parental permission by the Bioethics and Legal Work Group of the Newborn Screening Translational Research Network created under a contract from the National Institute of Child Health and Human Development to the American College of Medical Genetics and Genomics. Circumstances are outlined in which a waiver of documentation of permission or a waiver of permission may be ethically and legally appropriate in the NBS context. These guidelines do not constitute American Academy of Pediatrics policy.

Impact of specific medical interventions in early childhood on increasing the prevalence of later intellectual disability

IMPORTANCE

For the past 100 years, medicine in industrialized nations has become increasingly focused on specific medical interventions designed to improve the health of individual patients. Substantial evidence suggests that broader improvements in public health, nutrition, and economic well-being are more salient than medical or surgical interventions for the remarkable decrease in infant and child deaths since 1900. Less is known about the impact of specific medical interventions on morbidity such as intellectual disability (ID).

OBJECTIVE

To explore the impact of medical interventions in early childhood on increasing the prevalence of later ID, as reported in the literature from 1950 through 2000.

DESIGN

We reviewed the medical literature and other data from 1950 through 2000 to construct estimates of the condition-specific prevalence of ID over time. We further explored the existing literature to document historically relevant influences on condition-specific prevalence, including the introduction of effective interventions, the timing of these introductions, and the likelihood of their widespread use.

SETTING

Twentieth century United States and Western Europe.

PARTICIPANTS

Populations of children who received a life-saving intervention within the first 5 years of life and were evaluated for ID after 5 years of age.

MAIN OUTCOME MEASURES

Case-specific prevalence of ID from 1950 through 2000.

RESULTS

Low birth weight is associated with approximately 10% to 15% of the total prevalence of ID. No other new medical therapies introduced during this period were associated with a clinically significant increase in ID prevalence.

CONCLUSIONS AND RELEVANCE

Previous research has shown that specific medical interventions, such as newborn screening for congenital thyroid deficiency and phenylketonuria, have decreased the prevalence of ID approximately 16% in the United States since 1950. These results suggest that other medical interventions, particularly the advent of intensive care technologies, have also increased the prevalence of ID.

Do people with intellectual disability require special human subjects research protections? The interplay of history, ethics, and policy

People with intellectual disability (ID) have a long history of discrimination and stigmatization, and a more recent history of pride and self-advocacy. The early history suggests that people with ID are a vulnerable population and deserve special research protections as do some other groups; the disability rights movement of the late 20th century aligns people with ID more closely with the principle of autonomy that has guided clinical and research ethics for the last 40 years. In examining the history of people with ID and the prevailing framework of human subjects research protections in the United States, we conclude that people with ID do not require special protection in human subjects research. The protections that have already been put in place for all individuals, if conscientiously and effectively implemented, achieve the right balance between safeguarding the interest of human research subjects and empowering individuals who choose to do so to participate in research.

Adverse medical outcomes of early newborn screening programs for phenylketonuria

OBJECTIVE

Despite the success of current newborn screening programs, some critics have argued that in the 1960s hundreds of children with false-positive results for phenylketonuria suffered death or disability from treatment with restrictive diets. Medically adverse outcomes after false-positive results may be a reason to be cautious when expanding current newborn screening programs. We sought to determine if newborn screening programs for phenylketonuria before 1980 led to adverse medical outcomes in children with false-positive results.

PATIENTS AND METHODS

We examined the history of newborn screening programs for phenylketonuria in the United States. We reviewed the historical scholarship, conducted a systematic search for medical adverse outcomes, and interviewed key participants in the history of newborn screening programs.

RESULTS

We found no population-based studies of early screening programs for phenylketonuria. One author reported 2 infants treated with restrictive diets after false-positive results for phenylketonuria who were developmentally delayed, and there is unpublished evidence of 4 additional cases of inappropriate treatment, although adverse outcomes were not documented. There were also 4 published reports of adverse medical outcomes after treating children with phenylketonuria variants, as screening for phenylketonuria revealed infants with intermediate or transiently high levels of phenylalanine.

CONCLUSIONS

We found little evidence of death or disability that resulted from the inappropriate treatment of well children who were falsely identified by early newborn screening programs. Because the first decade of newborn screening typically reveals diagnostic and therapeutic complexity, systematic follow-up of screened populations and rapid dissemination of results may reduce morbidity/mortality rates.

Understanding autism: parents and pediatricians in historical perspective

Both primary care providers and subspecialists in pediatrics encounter families who are actively involved in the diagnosis and treatment of their children. Parents of children with an autism spectrum disorder in particular are often aware of scientific issues, and their expertise and desire for a medical cure for autism sometimes put them at odds with the medical team. We investigated the role of parents and advocates in autism research and treatment over the last 50 years. Our review of scientific publications and archival sources documents how parents and advocacy groups have done the following: (1) organized research funding; (2) constructed clinical research networks; (3) suggested new avenues for research; (4) popularized empirically based therapies; and (5) anticipated paradigmatic shifts in the understanding of autism. We believe that this historical account will help pediatricians and researchers recognize that families can contribute to expert understanding of complex medical conditions such as autism and that the existence of partnerships with families of children with autism is a critical component of future research and treatment programs.

What do residents learn by meeting with families of children with disabilities?: A qualitative analysis of an experiential learning module

PURPOSE

Attitudes of medical providers towards persons with disabilities can affect the quality of care their patients receive. The authors evaluated an experiential learning module to investigate what Paediatric and Medicine/Paediatric residents at the University of Miami/Jackson Memorial Hospital learn from visiting the homes of families with children who have disabilities.

METHODS

Families were recruited through a community-based parent organization. The families were instructed to discuss what it is like to have a child with a disability and to think about a primary message to give to residents during a 1-2 hour home visit. Since 1998, residents participated as part of the required Developmental Paediatrics rotation. They were instructed to write a one-page narrative description of their visit. The authors utilized the grounded theory of qualitative research and content analysis to count the key themes identified in the residents' descriptions.

RESULTS

Twenty-four families and 63 residents participated in the learning module. The resident observations yielded four major themes. Twenty-four per cent stated families needed more information; 79% noted that families face various obstacles, including financial (33%), medical providers' pessimism (29%), inter-personal family conflicts (27%) and medical system problems (22%); 49% of residents commented that families adjust and cope with their child's disability; and 27% of residents stated that the experience changed their insight about children with disabilities.

CONCLUSION

The authors' study suggests that a single home visit with the family of a child with a disability provides paediatrics and medicine/paediatrics residents with insights into the family's perspective on disability otherwise unattainable in a hospital-based training programme.

Universal newborn screening and adverse medical outcomes: a historical note

Universal newborn screening programs for metabolic disorders are typically described as a triumph of medicine and public policy in the US over the last 50 years. Advances in science and technology, including the Human Genome Project, offer the opportunity to expand universal newborn screening programs to include many additional metabolic and genetic conditions. Although the benefits of such screening programs appear to outweigh their costs, some critics have claimed that historical examples of inadvertent harm ensuing from false-positive screening results and subsequent inappropriate medical treatment should make us wary of expanding universal newborn screening. In this essay, we report the results of a review of the published literature to assess whether the extension of screening from at risk populations to all newborns led to substantial morbidity and mortality from misguided medical treatment. We provide a historical overview of universal newborn screening programs in the United States, and then focus on six early NBS programs: congenital hypothyroidism, phenylketonuria, congenital adrenal hyperplasia, galactosemia, sickle cell disease, and maple syrup urine disease. Our comprehensive search of published sources did not reveal a widespread problem of harm ensuing from medical treatment of children with false positive screening test results.

Impact of Specific Medical Interventions on Reducing the Prevalence of Mental Retardation

OBJECTIVE

To explore the impact of medical interventions on reducing the prevalence of mental retardation (MR) in the United States over the last 50 years.

DESIGN

We reviewed the medical literature and other data from 1950 to 2000 to construct estimates of the general and condition-specific prevalence of MR in the United States over time. We further explored the existing literature to document historically important influences on condition-specific prevalence, including the year that an effective intervention was introduced, the likelihood of success of the intervention, and the availability of such interventions nationwide. Specific conditions included congenital syphilis, Rh hemolytic disease of the newborn, measles, Haemophilus influenzae type B meningitis, congenital hypothyroidism, phenylketonuria, and congenital rubella syndrome.

SETTING

Twentieth-century North America.

PARTICIPANTS

Children with MR or 1 of the 7 specific conditions listed earlier.

MAIN OUTCOME MEASURES

Case-specific and general prevalence of MR from 1950 to 2000.

RESULTS

The prevalence of MR caused by a number of specific medical conditions has decreased sharply over the last 50 years. However, the incidence of each of these conditions is relatively low, and cases of MR due to these conditions represent, at most, 16.5% of the total number of cases of MR in 1950.

CONCLUSION

Although specific medical interventions have prevented thousands of cases of MR, their contribution to the overall prevalence of MR is relatively small.

Evidence-based community pediatrics: building a bridge from bedside to neighborhood

The American Academy of Pediatrics policy statement "The Pediatrician's Role in Community Pediatrics" encourages all pediatricians to partner with their communities to create and disseminate innovative programs that improve child health. This article describes 4 pillars of a bridge to evidence-based community pediatrics for pediatricians interested in pursuing effective community action: (1) collaborate with the community to establish a specific, short-term, health-related goal; (2) identify evidence-based best practice(s) for achieving the shared goal; (3) collaborate with the community to adapt this best practice to the community's unique assets and constraints; and (4) evaluate the project by using appropriate expertise. Practical elements of each pillar are described and illustrated by specific examples from community-based efforts of pediatricians and are accompanied by specific resources to aid pediatricians in their future community health work.