Human Acid-Labile Subunit Deficiency: Clinical, Endocrine and Metabolic Consequences

作者：Horacio M. Domené, Vivian Hwa, Jesús Argente, Jan Maarten Wit, Cecilia Camacho‐Hübner, Héctor Jasper, Jesús Pozo, Hermine A. van Duyvenvoorde, Shoshana Yakar, Olga V. Fofanova-Gambetti, Ron G. Rosenfeld · 发表于：Hormone Research in Paediatrics · 年份：2009 · DOI：10.1159/000232486 · 被引用次数：118 · 研究领域：Growth Hormone and Insulin-like Growth Factors、Genetic Syndromes and Imprinting、Lipid metabolism and disorders

The majority of insulin-like growth factor (IGF)-I and IGF-II circulate in the serum as a complex with the insulin-like growth factor binding protein (IGFBP)-3 or IGFBP-5, and an acid-labile subunit (ALS). The function of ALS is to prolong the half-life of the IGF-I-IGFBP-3/IGFBP-5 binary complexes. Fourteen different mutations of the human IGFALS gene have been identified in 17 patients, suggesting that ALS deficiency may be prevalent in a subset of patients with extraordinarily low serum levels of IGF-I and IGFBP-3 that remain abnormally low upon growth hormone stimulation. Postnatal growth was clearly affected. Commonly, the height standard deviation score before puberty was between -2 and -3, and approximately 1.4 SD shorter than the midparental height SDS. Pubertal delay was found in 50% of the patients. Circulating IGF-II, IGFBP-1, -2 and -3 levels were reduced, with the greatest reduction observed for IGFBP-3. Insulin insensitivity was a common finding, and some patients presented low bone mineral density. Human ALS deficiency represents a unique condition in which the lack of ALS proteins results in the disruption of the entire IGF circulating system. Despite a profound circulating IGF-I deficiency, there is only a mild impact on postnatal growth. The preserved expression of locally produced IGF-I might be responsible for the preservation of linear growth near normal limits.