甲状腺疾患と治療のジャーナル
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概要

Review Article on Congenital Hypothyroidism and Newborn Screening Program in Africa; the Present Situation and the Way Forward

Kayode A Adeniran and Mary Limbe

Congenital hypothyroidism (CH) is a condition that affects infants from birth (congenital) and results from partial or complete loss of thyroid function (hypothyroidism). CH has existed since antiquity, as exemplified by goitrous dwarfs in 400 BC in South America, writing about goiter from ancient Rome in the first century and descriptions of mental retardation and goitrous hypothyroidism in a lecture and subsequent publication by Paracelsus in the sixteenth century [1]. Non goitrous sporadic CH was not described until the beginning of the industrial revolution by Thomas Curling in 1850. By the end of the nineteenth century, thyroid extract were observed to effectively treat patients with CH, however not until the 1970s was it possible for mental retardation caused by CH to be virtually eradicated by early treatment as a result of early diagnosis through newborn screening [2]. During the second half of the twentieth century, various enzymatic defects in hormonogenesis were shown to be responsible for CH [3]. Immune mediated mechanism have also been proposed to cause thyroid dysgenesis, but a causal relationship has not been proven [4,5]. In the 1990s mutations in the extracellular domain of Thyrotropin (TSH) receptor in the ß sub unit of TSH and the transcription factors that regulate thyroid embryogenesis have been found to be rare cause of CH [6-10]. The suffering and heavy social and economic burden caused by congenital hypothyroidism prompted many countries to institute a formalized screening programme directed at newborns, just as a vaccination programme has become an integral part of child health care. In African countries however, this type of formalized service has not yet been established. Yet most African countries have crude birth rates (Nigeria-39.9, Kenya-39.2, south Africa-22.3 and Egypt-24.2) above the average (20.3 births per 1,000population) for the entire world, for African countries, the implementation of a universal neonatal screening programme will bring about a considerable improvement in child health care.