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Background: Inborn errors of metabolism comprise a set of more than 2000 known disorders which can result in significant morbidity and may be rapidly fatal. Diagnosing these disorders at birth and treating immediately, however, may often result in a normal to near-normal life for the affected infant. Thus, newborn screening (NBS) has saved or improved the lives of countless individuals since its inception in the 1960s., Content: This review covers NBS, from its early beginnings up to the current day practice. We follow the evolution of NBS, as well as describe the need and how disorders are added to NBS programs, the testing and how its performance is monitored, and the follow-up to the testing. We also briefly touch on NBS outside the United States., Summary: Newborn screening in the United States is a major public health success story and it continues to grow and evolve to cover more disorders and utilize new technological advances., (© Association for Diagnostics & Laboratory Medicine 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objectives/hypothesis: To document the history of hearing seeing in children and adults., Study Design: A literature search in all languages was carried out with the terms of hearing screening from the following sources: Pub Med, Science Direct, World Catalog, Index Medicus, Google scholar, Google Books, National Library of Medicine, Welcome historical library and The Library of Congress., Methods: The primary sources consisting of books, scientific reports, public documents, governmental reports, and other written material were analyzed to document the history of hearing screening., Results: The concept of screening for medical conditions that, when found, could influence some form of the outcome of the malady came about during the end of 19th century. The first applications of screening were to circumscribe populations, schoolchildren, military personnel, and railroad employees. During the first half of the 20th century, screening programs were extended to similar populations and were able to be expanded on the basis of the improved technology of hearing testing. The concept of universal screening was first applied to the inborn errors of metabolism of newborn infants and particularly the assessment of phenylketonuria in 1963 by Guthrie and Susi. A limited use of this technique has been the detection of genes resulting in hearing loss. The use of a form of hearing testing either observational or physiological as a screen for all newborns was first articulated by Larry Fisch in 1957 and by the end of the 20th century newborn infant screening for hearing loss became the standard almost every nation worldwide., Conclusions: Hearing screening for newborn infants is utilized worldwide, schoolchildren less so and for adults many industrial workers and military service undergo hearing screening, but this is not a general practice for screening the elderly., Level of Evidence: NA Laryngoscope, 131:S1-S25, 2021., (© 2021 The American Laryngological, Rhinological and Otological Society, Inc.)

The metabolic roles of carnitine have been greatly clarified over the past 50 years, and it is now well established that carnitine is a key player in mitochondrial generation of energy and metabolism of acetyl coenzyme A. A therapeutic role for carnitine in treatment of nutritional deficiencies in infants and children was first demonstrated in 1958, and since that time it has been used to treat a number of inborn errors of metabolism. Carnitine was approved by the US Food and Drug Administration in 1985 for treatment of 'primary carnitine deficiency', and later in 1992 for treatment of 'secondary carnitine deficiency', a definition that included the majority of relevant metabolic disorders associated with low or abnormal plasma carnitine levels. Today, carnitine treatment of inborn errors of metabolism is a safe and integral part of many treatment protocols, and a growing interest in carnitine has resulted in greater recognition of many causes of carnitine depletion. Notwithstanding, there is still a lack of data from randomized clinical trials, even on the use of carnitine in inborn errors of metabolism, although ethical issues may be a contributing factor in this regard., (© 2016 S. Karger AG, Basel.)

Newborn screening has evolved fast following recent advances in diagnosis and treatment of disease, particularly the development of multiplex testing and applications of molecular testing. Formal evidence of benefit from newborn screening has been largely lacking, due to the rarity of individual disorders. There are wide international differences in the choice of disorders screened, and ethical issues in both screening and not screening are apparent. More evidence is needed about benefit and harm of screening for specific disorders and renewed discussion about the basic aims of newborn screening must be undertaken., (© 2015 The Authors. Journal of Paediatrics and Child Health © 2015 Paediatrics and Child Health Division (Royal Australasian College of Physicians).)

In 1977, the Ministry of Health and Welfare (MHW) directed prefectural officials in charge of maternal and child health to start publicly funded newborn mass-screening (NBS) for phenylketonuria (PKU), maple syrup urine disease (MSUD), histidinemia, homocystinuria and galactosemia and a study group of MHW formulated the treatment guideline for the target diseases. In 1980, MHW launched the Japan Cooperative Project on Special Formula (JCPSF) to ensure a stable supply of special formula and also organized the committee for JCPSF. From 1977 to 2003, a study group of MHW conducted a follow-up study of the patients detected by the screening. From the follow-up it was concluded that dietary therapy was unnecessary for histidinemia and the screening for the disease was discontinued. In 1995, the guideline for the treatment of PKU was revised to keep lower blood phenylalanine levels. The guideline committee for the treatment of BH4 deficiency was establish in 1996 to obtain better prognosis. In 2012, the MHW decided to initiate publicly funded NBS using MS/MS for inborn errors of amino acid, organic acid, and fatty acid metabolism. The Japanese nationwide NBS has been performed for 35 years. This paper reviews the Japanese history of the development of NBS which has enabled more IEM patients to lead active and productive lives today.

After briefly recalling the main events leading to the establishment of newborn screening programmes, this paper details the early history of their introduction in Spain and sketches their expansion to cover the whole Spanish population. Spain is exceptional in that its screening methods have in general been based on planar chromatographic techniques developed or inspired by Louis I. Woolf, rather than on bacterial inhibition tests, as is illustrated by the practice of the newborn screening laboratory of Galicia (N.W. Spain)., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Akhenaten was one of Egypt's most controversial pharaohs, in part because of his strange appearance in images produced after he had declared Aten, the Sun-disc, his one-and-only god. Whether these were symbolic representations or realistic ones that indicate a deforming genetic disorder is the subject of continuing debate. The authors present evidence that the bizarre physical features portrayed in these images are not only realistic but were shared by many members of Egypt's 18th Dynasty. The features are best explained by either 2 different familial disorders-the aromatase excess syndrome and the sagittal craniosynostosis syndrome-or a variant of the Antley-Bixler syndrome caused by a novel mutation in one of the genes controlling the P450 enzymes, which regulate steroidogenesis and cranial bone formation.

Sir Archibald Garrod's concept of chemical individuality introduced a century ago provided the basis for the entire discipline of inborn errors of metabolism. Human disorders are defined by variation in disease-causing mutations, environmental influences, genetic factors other than the primary genetic defect, and evolution itself. Myriad examples support the prescience of Garrod with respect to these issues, each of which has therapeutic implications. Just as Garrod predicted that the future of biochemical genetics would be intertwined with the concept of chemical variability, we might forecast that variation will influence emotions, dreams, and the human thinking process itself.

Inborn errors of metabolism used to be regarded as simple monogenic traits, but a closer look at how different alleles of a gene determine different phenotypes shows that the molecular mechanisms in the individual case are often complicated. Most metabolic disorders represent a spectrum of phenotypes from normal via attenuated to severe (and sometimes prenatally fatal), and disease manifestation is often influenced by other specific genetic or exogenous factors. The terms 'dominant' or 'recessive' relate to the functional consequences of differing alleles in the (compound) heterozygous individual; the terms are irrelevant for homozygous individuals and inappropriate for X-linked disorders. Mutations affecting the same amino acid residue may be associated with different inheritance patterns. True dominant inheritance in metabolism is rare; it may be found e.g. in tightly regulated biosynthetic pathways or when minor changes in metabolite concentrations have a functional effect. Some disorders such as erythropoietic protoporphyria show pseudodominant inheritance due to prevalent loss-of-function polymorphisms in the general population and are better acknowledged as recessive traits. The term 'variable expressivity' is not helpful with regard to autosomal recessive disorders when variable phenotypes are explained by different mutations in the respective gene. Clonal unmasking of a heterozygous mutation through somatic loss of the second allele, the main pathomechanism in inherited tumour predisposition syndromes, is rare in metabolic disorders, but focal congenital hyperinsulinism is a notable exception. Somatic mosaicism for an OTC gene mutation is given as an example of an apparently heterozygous mutation pattern in a boy with an X-linked disease.

One hundred years ago--in 1908--Archibald Garrod delivered his four Croonian Lectures. In these formerly forgotten, but now famous, dissertations, Garrod first used the expression, 'inborn errors of metabolism', to describe four rare disorders: albinism, alkaptonuria, cystinuria, and pentosuria. This prescient work proposed that such disorders resulted from enzymatic defects in the catabolic pathways for amino acids and sugars. Thus, Garrod can rightfully be called the first human geneticist. Much influenced by his colleague Bateson, who brought Mendel's work to his attention, Garrod then was the first to apply Gregor Mendel's law of gene segregation to humans, the first to propose recessive inheritance in humans, and the first to point out the importance of consanguinity. He even mentioned the role of ethnicity in inherited disorders. This would have been legacy enough, but Garrod did much more. He wrote about such other 'modern' topics as genetic predisposition to common disorders; the critical importance of physicians who were also scientists; and the proper role of the university in society. Although Garrod's work and ideas were not appreciated during his lifetime, they have echoed and reverberated ever since. He can rightly be deemed one of the most profound intellectuals of the 20th century, whose bequests to science and medicine continue to increase in value. All of us who study inborn errors of metabolism and who apply our knowledge in the hope of improving the diagnosis and treatment of affected patients are, in a genuine sense, Garrodians.

Garrod presented his concept of 'the inborn error of metabolism' in the 1908 Croonian Lectures to the Royal College of Physicians (London); he used albinism, alkaptonuria, cystinuria and pentosuria to illustrate. His lectures are perceived today as landmarks in the history of biochemistry, genetics and medicine. Garrod gave evidence for the dynamic nature of metabolism by showing involvement of normal metabolites in normal pathways made variant by Mendelian inheritance. His concepts and evidence were salient primarily among biochemists, controversial among geneticists because biometricians were dominant over Mendelists, and least salient among physicians who were not attracted to rare hereditary 'traits'. In 2008, at the centennial of Garrod's Croonian Lectures, each charter inborn error of metabolism has acquired its own genomic locus, a cloned gene, a repertoire of annotated phenotype-modifying alleles, a gene product with known structure and function, and altered function in the Mendelian variant.

This article summarizes some findings of a research that I have pursued for the past 25 years, whose roots are immersed in the field of inherited metabolic disorders, and deal with different aspects of the vitamin biotin, starting with a patient with multiple carboxylase deficiency (MCD). Several of MCD clinical manifestations resemble those of infant malnutrition; we demonstrated that about one-third of infants with this common nutritional disorder were indeed biotin-deficient, and that this deficiency is metabolically significant, by studying urine instead of blood, studying urinary organic acids by gas chromatography-mass spectrometry. Remarkably, the metabolic abnormalities became apparent only after protein feeding was started, suggesting that this phenomenon may contribute to the worsening of malnourished individuals when they are abruptly fed. Afterwards, we studied biotin deficiency at the tissue level. Carboxylase activities and masses were significantly reduced in liver, kidney, muscle, adipose tissue, intestine, and spleen, but brain and heart were spared; their mRNAs remained unchanged. On the other hand, holocarboxylase synthetase (HCS) mRNA levels were markedly low in the deficient animals, and increased upon biotin injection. Over 2000 human genes have been identified that depend on biotin for expression. To probe into the "logic" of this enigma, we have started comparative studies among evolutionarily distant organisms, such as mouse and Saccharomyces cerevisiae, and we are now looking for biotin effects on specific genes and proteins, such as HCS and hexokinases, and on their proteomes.

The Society for Inherited Metabolic Disorders (SIMD) recently completed its 28th annual meeting and requested that its birth and development be documented. Accordingly, this communication reviews the origins of the SIMD and considers its development over the past three decades. Each decade had growth and differentiation regarding policy making, international connections, highlights and tragedies. Past contributions are defined and future directions for the SIMD are subjected to prophesy.

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., (Copyright (c) 2006 Wiley-Liss, Inc.)

Clinical disorders have intrigued the human mind for thousands of years. Many are enshrined in history as 'medical curiosities'. This report is a tribute to one of the greatest minds of modern genetics and medicine, Sir Archibald Edward Garrod (1857--1936), who brought forward the scientific study of inborn errors of metabolism. Garrod's concept of 'chemical individuality' with no awareness of 'genes' more than 100 years ago is an amazing example of futuristic thinking. His own words reflect this, 'Owing, as I believe, to their chemical individuality different human beings differ widely in their liability to individual maladies, and to some extent in the signs and symptoms which they exhibit'. The concept of chemical individuality is here to stay. Garrod has also provided insight into a number of scientific concepts and modern thinking.

Archibald Edward Garrod introduced a paradigm, new for its day, in medicine: Biochemistry is dynamic and different from the static nature of organic chemistry. It led him to think about metabolic pathways and to recognize that variation in Mendelian heredity could explain an 'inborn error of metabolism'. At the time, Garrod had no idea about the nature of a gene. Genes are now well understood, genomes are being described for one organism after another (including H. sapiens) and it is understood that genomes 'speak biochemistry (not phenotype)'. Accordingly, in the era of genomics, biochemistry and physiology become the bases of functional genomics and it is possible to appreciate why 'nothing in biology makes sense without evolution' (and nothing in medicine will make sense without biology). Mendelian, biochemical and molecular genetics together have revealed what lies behind the four canonical inborn errors described by Garrod (albinism, alkaptonuria, cystinuria and pentosuria). Both older and newer ideas in genetics, new tools for applying them, and renewed respect for the clinician-scientist will enhance our understanding of the human biological variation that accounts for variant states of health and overt disease; an 'unsimple' phenotype (phenylketonuria) is used to illustrate in some detail. What can be known and what ought to be done with knowledge about human genetics to benefit individuals, families and communities (society) is both opportunity and challenge.

Any young scientific discipline may experience difficulties in determining its position. For a young discipline placed at the juncture between potent branches of science with a long tradition, as is the case for Clinical Biochemistry, this is especially true. In such a situation, a look backwards to identify first origins and to follow trends of development can be helpful. Moreover, the close relationship between the history and the philosophy of science should provide insight into the nature of our present work and the potential for future work. Our discipline originated with the emergence of modern chemistry at the end of the 18th century. Methods for the chemical analysis of plant and animal material were developed first. The examination of chemical processes in living organisms followed. Only after these successes did chemical investigations of causes and mechanisms of human disease become possible. A few selected milestones in this evolution can illustrate the medical, philosophical, intellectual and social background which has shaped the rise of Clinical Biochemistry.