Herramientas de abordaje ante la consulta de diversidad sexual en la infancia y adolescencia

La identidad de género se define como la autopercepción de género, que puede o no corresponder con el sexo asignado al nacer. Aquellos niños que poseen una identidad de género que no coincide con el sexo biológico, son denominados "no conformes con su género", con "variante de género" o "transgénero". Existen evidencias crecientes que el cuidado y contención adecuados de estos niños/as y adolescentes pueden disminuir el daño y mejorar significativamente su inserción social y su calidad de vida. El objetivo de este artículo es proporcionar definiciones y orientaciones prácticas para el tratamiento endocrinológico de niños/as y adolescentes con disconformidad de género. Éste surge en respuesta a una demanda creciente en los últimos años. Se efectuó revisión bibliográfica basada en el análisis de las guías y publicaciones nacionales e internacionales, evaluando la aplicabilidad en nuestro medio y reforzando el seguimiento inter y transdisciplinario. Existe en la Argentina un marco legal encuadrado en la Ley 26.743 de "Identidad de Género" y a nivel internacional los Principios de Yogyakarta. El acompañamiento temprano de estos niños/as y adolescentes, en caso de persistencia o intensificación de la disconformidad de género, podría derivar en tratamientos orientados a disminuir las posibles comorbilidades asociadas, así como lograr cambios antropométricos, físicos y metabólicos, que deben ser conocidos y manejados por equipos transdisciplinarios en centros de referencia.

Gender identity is defined as gender self- perception, which may or may not correspond to the sex assigned at birth. Those children whose gender identity is different to the biological sex, are called "gender nonconforming," "gender diverse, or "transgender ". There is growing evidence that with supportive, increasing visibility and social acceptance of gender diversity, their social integration and quality of life can be significantly improved. The objective of this article is to provide definitions and practical guidelines for the endocrinological treatment of children and adolescents with gender disconformity. It arises in response to a growing demand in recent years. A bibliographic review was carried out, based on the analysis of national and international guides and publications, evaluating inter and multidisciplinary follow up and applicability among us. There is a legal framework in Argentina, supported by the law 26.743, about "Gender identity", and an internationally one, expressed in the Yogyakarta Principles. In case of persistence or intensification of gender disconformity, with early support and treatment, harms could be meliorated and the possible associated comorbidities can be significantly improved. Anthropometric, physical and metabolic changes should be known and managed by multidisciplinary teams in reference centers

Acid-labile subunit deficiency: phenotypic similarities and differences between human and mouse.

IGF-I and IGF-II (IGFs) form higher molecular weight complexes with specific binding proteins (IGFBP-1 to -6). These complexes are referred to as binary complexes consisting of IGF-I or IGF-II and one IGFBP, or as ternary complexes each consisting of either of IGF-I or IGF-II, IGFBP-3 or -5, and an acid-labile subunit known as ALS. Ternary complex formation restricts the IGFs to the circulation and prolongs their half-life. Recently, the development of an animal model for ALS deficiency (the ALS-KO mouse) and the identification of a patient with an inactivating mutation in the IGFALS gene have provided the opportunity to assess the physiological role of this protein in the circulating IGF system. ALS deficiency has no effect on fetal growth in both the ALS-KO mice and the ALS-deficient patients. A modest reduction in post-natal growth in the null ALS mice and in the ALS-deficient patients was observed. The plasma concentrations of IGF-I and IGFBP-3 were markedly reduced both in ALS-KO mice and in the ALS-deficient patients. Basal GH levels remained normal in the ALS-KO mice and moderately increased in the ALS-deficient patients. Insulin-resistance was present in the ALS-deficient patients but not in the ALS-KO mice. Reduced bone mineral density (BMD) was present in mice and human ALS deficiency. Phenotypic features of complete ALS deficiency, that are very similar in mouse and human, include: a) the inability to form ternary complex, b) the small growth impairment in spite of the marked reduction in circulating IGF-I, and c) the reduction in BMD. On the other hand, insulin resistance and pubertal delay were observed only in human ALS deficiency. These findings underlie the important physiological role of ALS in the maintenance of the circulating IGF-I reservoir. Both models will be useful in identifying the respective roles of plasma and locally derived IGF-I in regulating metabolism and growth of specific tissues.

Neonatal screening program for congenital adrenal hyperplasia: adjustments to the recall protocol.

OBJECTIVE: To evaluate the influence of gestational age (GA) and birth weight (BW) on 17 alpha-OH-progesterone (17-OHP) levels with respect to their impact on the recall rate of neonatal screening programs for congenital adrenal hyperplasia (CAH). PATIENTS AND METHODS: In June 1997 we began a pilot screening program for CAH measuring 17-OHP using a fluoroimmunoassay method (DELFIA) on dried blood spots. Until September 1999, 24,153 babies were screened. Among them, we analyzed the levels of 17-OHP in 1,313 samples from healthy preterm babies (23-36 weeks) and 1,500 term babies (>37 weeks), grouped according to GA and BW. All preterm babies underwent another sampling in their 2nd week of life. RESULTS: 5 CAHs were detected. The 30-nmol/l cutoff limit for 17-OHP in blood corresponded to the calculated 99th percentile in term newborns, while in preterm babies higher levels were found. GA and BW correlated inversely with 17-OHP levels. CONCLUSION: GA and BW were useful tools to adjust cutoff levels, obtaining a significant reduction in follow-up testing and psychological stress for families. The high false-positive recall rate in preterm babies can be substantially lowered with adjusted GA and/or BW criteria.

Usefulness of thyroxine and free thyroxine filter paper measurements in neonatal screening for congenital hypothyroidism of preterm babies.

INTRODUCTION: Low thyroxine (T4) with normal thyroid stimulating hormone (TSH) is a well known condition in preterm (PT) infants. The establishment of T4 and freeT4 (FT4) values in filter paper dried blood spots in PT could provide useful information in the neonatal period. OBJECTIVE: To study T4 and FT4 levels in dried blood filter paper samples of PT and full term (FT) babies. METHODS: We measured T4 by fluoroimmunoassay (FIA) DELFIA and TSH by IFMA DELFIA (Wallac Inc Turku, Finland) in 193 PT (26 to 37 weeks of gestational age (GA)) in samples from the first and second week of life and in 153 FT babies in the first week of life. In 131 PT and 31 FT we determined FT4 in filter paper blood spots using FIA (Alonso Fernandez J). Infants were grouped according to GA. RESULTS: There was a significant difference in T4 between PT and FT (p < 0.001). The lowest T4 levels were at 26 to 29 weeks GA. T4 values were lower in the second week. FT4 in PT up to 35 weeks GA, during the first week, was significantly different with FT infants (G1 to G3 p < 0.01, G4 p < 0.05). FT4 values in the first and second weeks of life did not vary. CONCLUSIONS: T4 values were significantly lower in PT than in FT neonates, increasing with GA. PT infants had low T4 with normal FT4 values. This could suggest a decreased thyroxine binding globulin (TBG) or decreased protein binding and/or an adaptative mechanism that would not require therapeutical intervention.

Congenital adrenal hyperplasia and early newborn screening: 17 alpha-hydroxyprogesterone (17 alpha-OHP) during the first days of life.

OBJECTIVE: Definition of upper limits for 17 alpha-hydroxyprogesterone (17 alpha-OHP) is important as its measurement is used in screening for congenital adrenal hyperplasia. This study aimed at investigating the cut off concentrations in relation to the day of sample collection. METHODS: 17 alpha-OHP concentration was determined in dried filter paper blood spots taken from cord blood and by heel pricking up to the sixth day of life. A sensitive fluoroimmunoassay (DELFIA) method was used. Samples from 1091 apparently health full term neonates were tested. Samples were separated according to the age of sampling. RESULTS: The 17 alpha-OHP (nmol/l blood) (median and 97.5th centile) concentrations according to the age of sampling were: cord blood (n = 126) 123.7, 265.6; first day 0-6 hours (n = 30) 49.4, 80.3; 6-12 hours (n = 57) 42.7, 79.8; 12-18 hours (n = 58) 38.1, 62.7; 18-24 hours (n = 67) 28.8, 49.7; second day 24-36 hours (n = 51) 23.6, 43.3; 36-48 hours (n = 63) 19.9, 35.4; third day (n = 200) 10.6, 23.5; fourth day (n = 197) 8.8, 20.8; fifth day (n = 76) 6.4, 18.3; sixth day (n = 166) 6.6, 19.4. CONCLUSION: Cord 17 alpha-OHP concentrations were very high as previously described, probably owing to steroid production by fetal adrenal glands. Therefore, cord blood is not useful for screening purposes. Thereafter there is a gradual decline in 17 alpha-OHP median concentrations. A cut off value of 30 nmol/l blood was useful in samples obtained after 48 hours of life. However, cut off values before 48 hours should be adjusted according to the sampling time.