The consequences of extended newborn screening programmes: Do we know who needs treatment?

Abstract

The development of an evidence base for newborn screening is especially difficult because of the rarity of disorders now detectable. One consequence of expanded newborn screening is that physicians are being called upon to manage asymptomatic babies with persistent biochemical disturbances that indicate likely enzyme deficiencies. Some of these may be very mild. There is not always agreement as to who should be treated. Particular problems are seen with disorders that were previously thought very rare but are now found frequently by newborn screening. Some of these disorders appear benign or nearly so, and in the present state of knowledge should clearly not be included in routine newborn screening panels.

Sweet and Sour Aspects of Medium-Chain Acyl CoA Dehydrogenase Deficiency

“…Hence, early clinical manifestation due to an IEM might precede screening results and deserves our clinical attention. Data from a well-described population in Australia showed clinical symptoms by 5 days of life in 43 of 177 children with an IEM detectable by tandem mass spectrometry, excluding phenylketonuria [2] . These 43 cases included 19 newborns with urea cycle defects, 11 organic acidurias, 8 medium chain acyl-CoA dehydrogenase (MCAD) deficiency and 5 other disorders of mitochondrial fatty acid oxidation (mFAO).…”

Enzyme Replacement Therapy and Extended Newborn Screening for Mucopolysaccharidoses: Opinions of Treating Physicians

“…These are issues that were raised by the affected individual/family group but not the physicians (Hayes et al 2007). Guidelines state that NBS should only be introduced if a disorder is severe, and early diagnosis results in a better outcome for the affected individual (Wilcken 2008). Early Enzyme Replacement Therapy and Extended Newborn Screening for Mucopolysaccharidoses: Opinions of Treating Physiciansdiagnosis afforded by NBS might allow timely genetic counseling and family planning, and was raised as a positive outcome by both physicians and affected individuals/ families as an important potential benefit of NBS.…”

Genetic Screening

“…Tandem mass spectrometry enables measurement of numerous metabolites and more than 50 metabolic disorders, some still poorly characterized or lacking definitive treatment (17,45). In addressing technology of this scope, policy makers need explicit criteria to determine whether to add a test to the newborn screening panel.…”

“…Lack of data has been a persistent difficulty for newborn screening policy makers: the conditions in question are rare, making systematic observation difficult; and the clinical presentations often require immediate action, making implementation of clinical trials difficult and sometimes unethical (45,48). However, the Secretary's Advisory Committee on Heritable Diseases in Newborns and Children endorsed the American College of Medical Genetics recommendations (49), as did other organizations concerned with child health (50,51); most states now screen for the recommended conditions (Table 3).…”