Electronic Letters to:

Endocrine Care: Karen E. Heath, Jesús Argente, Vicente Barrios, Jesús Pozo, Francisca Díaz-González, Gabriel A. Martos-Moreno, María Caimari, Ricardo Gracia, and Ángel Campos-Barros Primary Acid-Labile Subunit Deficiency due to Recessive IGFALS Mutations Results in Postnatal Growth Deficit Associated with Low Circulating Insulin Growth Factor (IGF)-I, IGF Binding Protein-3 Levels, and Hyperinsulinemia J Clin Endocrinol Metab 2008; 93: 1616-1624 [Abstract] [Full text] [PDF]

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Primary ALS deficiency – correct nomenclature

Angel Campos-Barros, Karen E. Heath   (3 July 2008)

Fungible terminology, what’s primary and what’s secondary?

Arlan L. Rosenbloom   (22 June 2008)

Primary ALS deficiency – correct nomenclature 3 July 2008
Angel Campos-Barros, Ph.D Dept. of Medical Genetics, Hospital Universitario La Paz, Madrid, Spain, Karen E. Heath Send letter to journal: Re: Primary ALS deficiency – correct nomenclature acamposb.hulp{at}salud.madrid.org Angel Campos-Barros, et al.	We are writing in response to Dr. Rosenbloom´s E-letter entitled "Fungible terminology, what’s primary and what’s secondary?" (1) regarding our report on primary acid-labile subunit deficiency due to IGFALS mutations (2). Although we partially agree with his comments regarding the misleading use by others of the term “primary” in the context of IGF-I deficiency, we believe that it is helpful in conceptually characterizing and succinctly differentiating this distinct form of ALS deficiency from that secondary to GH deficiency or insensitivity. Moreover, the ensuing "oxymoron" pointed out by Dr. Rosenbloom would only result from the (incorrect) application of the previously mentioned misleading definition of primary IGF-I deficiency, and not from the an appropriately strict definition of primary: one that refers to ALS deficiency due to IGFALS gene mutation, as Dr. Rosenbloom stated by himself. References: 1. Rosenbloom AR. 2008 Fungible terminology, what’s primary and what’s secondary? J Clin Endocrinol Metab: E-letter 22 June 2. Heath KE, Argente J, Barrios V, Pozo J, Díaz-González F, Martos- Moreno GA, Caimari M, Gracia R, Campos-Barros A. 2008 Primary acid-labile subunit deficiency due to recessive IGFALS mutations results in postnatal growth deficit associated with low circulating insulin growth factor (IGF)-I, IGF binding protein-3 levels, and hyperinsulinemia. J Clin Endocrinol Metab 93:1616-1624
Fungible terminology, what’s primary and what’s secondary? 22 June 2008
Arlan L. Rosenbloom, MD University of Florida Send letter to journal: Re: Fungible terminology, what’s primary and what’s secondary? rosenal{at}peds.ufl.edu Arlan L. Rosenbloom	In their excellent report on "primary acid labile subunit deficiency" due to recessive IGFALS mutations, Heath et al. (1) provide reinforcement for the recent proposal to eliminate the ambiguous terms primary and secondary from classification of disorders of the GH IGF-I axis (2). The authors apply an appropriately strict definition of primary when speaking of the ALS deficiency due to mutation of the IGFALS gene. Nonetheless, primary is an unnecessary modifier when, as here, the specific causation is designated. The biochemical result of the IGFALS mutation in "primary" ALS deficiency is, by definition, "secondary" IGF-I and IGFBP3 deficiency. Others, however, have declared that any deficiency in IGF-I resulting from abnormality in response to GH is primary IGF-I deficiency (IGFD), including GH receptor deficiency, STAT5B mutations, IGF-I gene mutations, and ALS gene mutation (3). Thus, such a classification would result in oxymoronically labeling the condition that Heath et al. (1) have reported as "primary IGFD due to primary ALS deficiency". And classifying deficiency of a specific product of GH-GH receptor interaction due to mutation of the gene for the target protein as a "primary" deficiency, as Heath et al. (1) have done, would result in designating IGF-I deficiency due to mutations of the IGF-I gene with "primary IGFD due to primary IGFD". References 1. Heath KE, Argente J, Barrios V, Pozo J, Díaz-González F, Martos- Moreno GA, Caimari M, Gracia R, Campos-Barros A. 2008 Primary acid-labile subunit deficiency due to recessive IGFALS mutations results in postnatal growth deficit associated with low circulating insulin growth factor (IGF) -I, IGF binding protein-3 levels, and hyperinsulinemia. J Clin Endocrinol Metab 93:1616-1624 2. Rosenbloom AL, Guevara-Aguirre J. 2006 Controversy in clinical endocrinology: reclassification of insulin-like growth factor I production and action disorders. J Clin Endocrinol Metab 91:4232-4234 3. Ranke MB. 2006 Defining insulin-like growth factor-I deficiency. Horm Res 65,Suppl 1:9-14