The importance of newborn screening

Newborn screening system: Safety, technology, advocacy

Newborn screening (NBS) is more than 50 years old and has proven to be a powerful and successful public health system. NBS must be regarded as a system and not simply as a test. We need to work as a community to improve the culture of safety for the NBS system and thereby to reduce the risk of babies being missed by the NBS system. Adding new technologies will not prevent system failures; that will require adherence to the culture of safety. Some have argued that every newborn should have their genome sequenced at birth and this sequencing could be part of NBS. However, NBS has depended on biomarker phenotypes throughout its history and our understanding of the relationships between genotype and phenotype is imperfect. Therefore, we should avoid being seduced by genomic sequencing technology and continue to focus on phenotypic biomarkers in NBS.

Steroid 21-hydroxylase deficiency in congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) refers to a group of inherited genetic disorders involving deficiencies in enzymes that convert cholesterol to cortisol within the adrenal cortex. There are five key enzymes involved in the production of cortisol. Of these key enzymes, deficiency of 21-hydroxylase is the most commonly defective enzyme leading to CAH representing more than 90% of cases. The low adrenal cortisol levels associated with CAH affects the hypothalamic-pituitary-adrenal negative feedback system leading to increased pituitary adrenocorticotropic hormone (ACTH) production, which overstimulates the adrenal cortex in an attempt to increase cortisol production resulting in a hyperplastic adrenal cortex. The deficiency of enzyme 21-hydroxylase results from mutations or deletions in the CYP21A2 gene found on chromosome 6p. The disorder is transmitted as an autosomal recessive pattern and specific mutations may be correlated to enzymatic compromise of varying degrees, leading to the clinical manifestation of 21-hydroxylase deficiency (21-OHD) CAH.

Current situation and prospects of newborn screening and treatment for Phenylketonuria in China - compared with the current situation in the United States, UK and Japan

Phenylketonuria (PKU) is a treat-able and prevent-able inborn error of metabolism which leads to severe mental retardation and neurobehavioral abnormalities. A screening program, especially for early detection, combined with a Phe-restricted therapeutic diet can help to control the process of PKU of most patients. The China government has put more emphasis on newborn screening and treatment against PKU, yet by comparing the situation of newborn screening and treatment against PKU in China and the relatively developed countries - United States, United Kingdom and Japan, the newborn screening and treatment against PKU in China is relatively weak and many deficiencies are found. More studies concerning multi-stage target blood Phe concentration criteria, a policy that requires newborn screening has to be taken, better financial support for newborn screening, publicity for newborn screening, and national guidelines for treatment of PKU may be prospects in China and may provide some support for better development of newborn screening and treatment against PKU in China.

Newborn blood spot screening in four countries: stakeholder involvement

While newborn blood spot screening has historically been viewed as a public health success, the potential harms and benefits are more finely balanced for new conditions being considered for program expansion. We highlight complex issues that must be addressed in policy decisions, which in turn requires a consideration of many stakeholder perspectives. Using national policy documents from the United Kingdom, the United States, Australia, and Canada, we describe the participation of stakeholder organizations in the newborn screening policy process, how such organizations have incorporated stakeholder views into their own policy writing, and their recommendations for inclusiveness. Stakeholder participation in newborn screening decision-making is widely acknowledged as important, and many methods have been endorsed - consultation as well as direct or indirect input into policy development. Differences across organizations and jurisdictions raise questions about the most effective approaches for facilitating inclusiveness, suggesting a need for formal evaluative research.

Critical role of the March of Dimes in the expansion of newborn screening

Expansion of newborn screening (NBS) has been driven primarily by a combination of advances in technology and medical treatment, and the sustained advocacy efforts of consumers and voluntary health organizations. The longstanding leadership of the March of Dimes has been credited by many as a critical factor in the expansion and improvement of state NBS programs. From the historic vantage point of four decades of March of Dimes involvement with newborn screening, this report reviews the unique origin of the first newborn screening test, and identifies from this point of origin several of the elements which still define the evolution of advocacy for NBS today. It also documents activities at the federal level and in seven states that have lead to expanded screening for newborns. Advances in NBS technology and medical treatment have informed policy development. Mobilization of volunteers and focused advocacy activities have brought about expansion of screening opportunities for newborns across the United States. But more work is needed. Continued application of the effective strategies identified in this report will help assure that all families have the best possible chance of assuring that their newborns do not have to suffer the complications of conditions that we know can be treated effectively.

Newborn Screening: A Literature Review

Newborn screening is the largest genetic testing effort for newborns in the U.S. Its purpose is to identify newborns who are at risk for metabolic, endocrine, or hematologic disorders. A review of the literature was conducted to determine the benefits of newborn screening; specimen collection timing and handling; ethical considerations of screening; as well as current practices regarding consent, notification of results, and follow-up procedures. The use of tandem mass spectrometry for expanded newborn screening and postmortem diagnosis of unexplained infant death was also reviewed. This article is intended to educate health care providers in the areas of controversy that surround the U.S. newborn screening program, with the hope of encouraging further research in this important area of newborn care.

Attitudes of genetic counselors towards expanding newborn screening and offering predictive genetic testing to children

There is movement to expand newborn screening (NBS) to include conditions that challenge the traditional public health screening criteria. Little is known about the attitudes of genetic counselors towards expanding NBS and offering predictive genetic tests to children. For our study genetic counselors completed an internet survey posted on the National Society of Genetic Counselors Listserv regarding five conditions: cystic fibrosis (CF), Duchenne muscular dystrophy (DMD), glucose-6-phosphate dehydrogenase deficiency (G6PD), fragile X (FraX), and type 1 diabetes (T1D). The survey addressed attitudes towards: (1) testing high-risk infants; (2) mandatory NBS; (3) population screening beyond the newborn period; and (4) testing one's own child. Two hundred sixty-seven usable surveys were received. Over two-thirds of respondents supported testing high-risk infants for all conditions except T1D (22%). CF was the only condition for which there was majority support for both mandatory NBS (56%) and later population screening (60%). For all other conditions, later population screening was preferred over NBS (P <or= 0.01). Genetic counselors were most likely to test their own child for CF (46%) and least likely to test their own child for T1D (6%). For each condition, genetic counselors were more likely to support NBS if they chose to screen their own newborn (P < 0.001). Attitudes towards NBS were not influenced by year of graduation or professional experience. We can conclude that genetic counselors are supportive of targeted testing of high-risk infants. They prefer voluntary population screening with consent to mandatory NBS for conditions that challenge Wilson and Jungner criteria. Their support for NBS correlates with their interest in testing their own children and not with professional experience.

Characterization of neuronopathic Gaucher disease among ethnic Poles

PURPOSE

Gaucher disease is a common lysosomal storage disease that results from inherited mutations in the gene (GBA) encoding acid beta-glucosidase (GCase). Here, the clinical and molecular findings of the subacute neuronopathic variant are delineated among ethnic Poles.

METHODS

Longitudinal studies of visceral, bony, and central nervous system involvement are delineated clinically. Complete gene GBA sequencing was used to characterize the mutations and haplotypes in this population.

RESULTS

A greater frequency of subacute neuronopathic Gaucher disease (type 3) is present among ethnic Poles compared with other European countries. Two type 3 phenotypes were found: The first was an early-onset variant with massive visceral disease, progressive kyphoscoliosis, mild cognitive deficits, and survival for three or more decades. This variant resembles the "Norrbottnian" Swedish phenotype. The other variant had more severe progressive central nervous system disease, milder visceral involvement, and absence of kyphoscoliosis. Myoclonus was present in some patients. Neither variant had bone crises and/or pain as major components. The L444P/L444P genotype was most common, but on several different haplotype backgrounds. Other alleles encoded D409H, V305L, and E326K/A446P on various haplotypes.

CONCLUSIONS

These studies provide additional expansion of the type 3 genotypes with some commonalities with and differences from other reported variants. Also, such phenotypic expansion should be expected in the other variants of Gaucher disease as the spectrum of ethnic variation becomes more fully delineated.

Main Report

Background:

Objectives:

Methods:

Results:

Conclusions:

Pediatricians' attitudes toward expanding newborn screening

OBJECTIVE

Traditional population screening focuses on conditions for which early treatment prevents severe morbidity and mortality. The classic example in pediatrics is newborn screening for phenylketonuria, which began in the 1960s. In 1968, Wilson and Jungner delineated 10 criteria that would justify population screening. These criteria have been reaffirmed by many newborn screening task forces as the standard for adding conditions to newborn screening programs. Today, however, some newborn screening programs are expanding to include conditions that may not meet all of the traditional screening criteria. Little is known about pediatricians' attitudes toward expanding screening. We examine the attitudes of pediatricians and pediatric subspecialists toward screening for cystic fibrosis (CF), Duchenne muscular dystrophy (DMD), fragile X, and type 1 diabetes.

METHODS

A cross-sectional survey was conducted of 600 pediatricians, including those who are members of the section of genetics, endocrinology, pulmonology, and neurology of the American Academy of Pediatrics. For each condition, pediatricians were queried about (1) testing high-risk infants, (2) newborn screening, and (3) population screening or testing beyond the newborn period. Demographic data were also collected.

RESULTS

A total of 232 (43%) of 537 eligible pediatricians returned surveys. More than 75% support testing high-risk infants for all conditions except type 1 diabetes. CF was the only condition for which >50% supported newborn screening. Newborn screening was preferred over screening older infants for all conditions except fragile X. Subspecialty affiliation did not have a significant impact with respect to attitudes about testing high-risk children, newborn screening, or screening beyond infancy. We analyzed the data by the number of patients with the queried condition under the physician's care and by the number of affected family members. Neither aspect was significant. We also analyzed the data by gender, by year of residency graduation, and by geographic location. None of these factors revealed significant differences in responses. For each condition, 8% to 41% of physicians would personally choose to test their own infant. We found that physicians' opinion about what they would want for their own children correlated with their attitude about population newborn screening. Those who would personally choose testing of their own infants were highly likely to support newborn screening for CF (98%), DMD (94%), and fragile X (98%), but only 78% of those who would personally opt for newborn screening of type 1 diabetes would also endorse population-based screening. This was statistically significant for each condition. Those who would choose not to test their own infants were significantly less likely to support newborn screening of the general population. One third of those who did not want to test their own newborns for CF supported population screening, whereas only one fifth supported DMD and fragile X population screening. For type 1 diabetes, 98% of those who would not personally choose newborn testing did not want it offered as a population screening program.

CONCLUSIONS

Most physicians support diagnostic genetic testing of high-risk children but are less supportive of expanding newborn screening, particularly for conditions that do not meet the Wilson and Jungner criteria. Willingness to expand newborn screening does not correlate with professional characteristics but rather with personal interest in testing of their own children.

Newborn screening: rationale for a comprehensive, fully integrated public health system

Newborn screening has existed for approximately four decades. During that period of time, newborn screening has evolved conceptually from a laboratory test for a single disorder, phenylketonuria (PKU), to a multi-part public health system involving education, screening, diagnostic follow-up, treatment/management, and system evaluation. At a time when newborn screening is recognized as a model for predictive medicine, it also faces critical challenges that will determine its future credibility and viability. In order to understand these challenges, it is helpful to review briefly the history of newborn screening.

The Colorado newborn hearing screening project, 1992-1999: on the threshold of effective population-based universal newborn hearing screening

OBJECTIVE

Although previous studies have documented the feasibility and benefits of universal newborn hearing screening in selected hospitals, none have reviewed the effectiveness of regionally mandated participation of large numbers of hospitals with variable levels of motivation to succeed. The purpose of this study was to measure hospital participation and overall screening success in a statewide program for universal newborn hearing screening and to track improvements in program establishment and outpatient follow-up over time.

METHODS

Four Colorado hospitals began voluntarily performing hearing screening before hospital discharge on all newborns in 1992. By 1996, 26 Colorado hospitals were participating in universal newborn hearing screening. The publication of screening results from these early years served as a catalyst for legislation requiring increased hospital participation in establishing universal screening programs. Data systems were subsequently developed to improve statistical tracking and follow-up. Eight years' worth of cumulative study data as well as the results from calendar year 1999 (the year of greatest hospital participation) were reviewed for collective measures of successful screening and follow-up. Three hospitals did not initiate newborn hearing screening programs until after the study period ended in 1999. Of the 57 hospitals that were screening newborns in 1999, the chosen method of screening at 52 hospitals was automated auditory brainstem response testing; 3 hospitals used otoacoustic emission testing, and the remaining 2 hospitals used 2-stage screening. Hearing loss was defined as a threshold of 35 decibels or greater in 1 or both ears at the time of confirmatory testing.

RESULTS

During the full 8-year study period, 1992 to 1999, 148 240 newborns were screened. A total of 291 infants who were born during the study period received a diagnosis of congenital hearing loss. In this cohort of 291 children, the cumulative frequency of bilateral hearing loss was 71% (range: 48%-94% by calendar year), the frequency of sensorineural hearing loss was 82% (range: 67%-88%), and the frequency of 1 or more risk factors was 47% (range: 37%-61%). During calendar year 1999, a total of 63 590 births were recorded at 60 birthing hospitals in Colorado. The families of 263 (0.4%) of these newborns refused newborn hearing screening. Of the remaining 63 327 newborns, 87% (55 324 infants) were screened for hearing acuity before hospital discharge, a far greater percentage than the 19% of all newborns screened during the first 5 years of voluntary hospital participation, and approaching the American Academy of Pediatrics's recommendation of 95% of newborns completing hospital-based testing in a successful screening program. As a result of this statewide hearing screening program, congenital hearing loss was diagnosed in 86 Colorado newborns during 1999, representing an occurrence rate of approximately 1 affected child in every 650 newborns. In this group of 86 infants, 59 had bilateral sensorineural hearing loss, 17 had unilateral sensorineural hearing loss, 4 had bilateral conductive hearing loss, and 6 had unilateral conductive hearing loss. Mild hearing loss was present in 6 infants, moderate hearing loss was present in 42 infants, severe hearing loss was present in 33 infants, and profound hearing loss was present in the remaining 5 infants. Only 32 of the 86 affected newborns in 1999 had 1 or more risk factors for hearing loss subsequently identified. After failing an initial hospital-based screening at 1 of the 57 participating hospitals in 1999, 2.3% of infants screened (1283 newborns) were referred for follow-up testing, easily exceeding the standard of <4% recommended by the American Academy of Pediatrics. Similarly, the false-positive rate of 2.2% during 1999 exceeded the recommended standard of <3%. Of the infants who failed their initial screening, 76% (978 infants) had documented follow-up testing to confirm or exclude congenital hearing loss, a percentage significantly improved from a follow-up rate of 48% during the first 5 years of screening, although not yet achieving the standard of 95% recommended by the American Academy of Pediatrics. Nine participating hospitals, however, were able to document appropriate follow-up for 95% or more of the infants who failed their initial screening tests. The median age of diagnosis of congenital hearing loss during 1999 was 2.1 months; 71% of affected infants were identified by 3 months of age (the recommended standard for age of diagnosis), and 92% of affected newborns were identified by 5 months of age. Measures of screening success were compared for large, mid-sized, and small hospitals. Increasing hospital size, as measured by the number of births per year, was associated with an increasing percentage of newborns who were successfully screened. It was notable that smaller hospital size was associated with increased referral rates for follow-up testing, whereas larger hospital size was associated with the highest recapture rate for follow-up testing.

CONCLUSIONS

Universal screening for congenital hearing loss is demonstrated to be feasible in a large regional effort of legislatively mandated participation. The success of such an endeavor is dependent on educational efforts for community professionals, commitment on the part of program planners, and data systems that more accurately track and recall infants who fail initial hospital-based screening.

U.S. newborn screening policy dilemmas for the twenty-first century

Newborn screening has traditionally referred to biochemical testing for inherited disorders, generally metabolic in origin, that are usually correctable by dietary or drug interventions. As new tests have been developed, state public health newborn screening systems have slowly evolved without the benefit of national policies. Thus, newborn screening program changes, when viewed nationally, have been uncoordinated. The net result has been unequally applied mandated screening and, consequently, unequal availability of related public health disease prevention services. Technological advances in laboratory testing over the past 10 years have resulted in limited program changes in some state newborn screening systems, and even greater program disparities. A recent Newborn Screening Task Force identified numerous issues of concern and proposed elements for a plan of action involving public health programs, healthcare providers, and consumers. This minireview details past policy history in newborn screening and identifies some of the current issues confronting programs as they seek to move ahead with the technologies and medical treatments for the twenty-first century.