Síndrome de insensibilidad a andrógenos: revisión bibliográfica a propósito de 5 casos / Androgen insensitivity syndrome: literature review about 5 cases

El síndrome de insensibilidad a andrógenos (AIS en la sigla inglesa) es una entidad muy poco frecuente en endocrinología. Se caracteriza por la mutación del receptor de andrógenos de magnitud variable, por medio del cual individuos 46,XY no se virilizan normalmente, a pesar de conservar sus testículos y tener concentraciones de testosterona en rango masculino. El cuadro clínico es variable y depende la profundidad de la alteración del receptor. En un extremo, hay casos de insensibilidad androgénica completa (CAIS) con fenotipo femenino. En el otro extremo hay insensibilidad parcial (PAIS) que se extiende desde el fenotipo femenino, con o sin ambigüedad genital, hasta los casos de hombres infértiles o con subvirilización, que presentan insensibilidad androgénica más leve. En los fenotipos femeninos, los testículos suelen estar en posición ectópica y aquellos ubicados dentro del abdomen tienen riesgo de malignizarse, por lo que suelen extirparse. Estos son los casos de más difícil manejo, pues aparte de la necesidad de gonadectomía seguida de terapia hormonal femenina, existe una vagina estrecha y en fondo de saco ciego y que suele requerir corrección quirúrgica para permitir la actividad sexual. En este trabajo presentamos 5 casos de AIS vistos recientemente en 2 centros clínicos de Santiago y que ilustran la heterogeneidad de presentación. Además, hacemos una revisión actualizada de los criterios diagnósticos, los tratamientos más adecuados y el manejo global de esta condición.

The Androgen insensitivity syndrome (AIS, in its English acronym) is a very rare entity in endocrinology. It is characterized by a variable magnitude androgen receptor mutation, whereby 46, XY individuals are not normally virilized, despite retaining their testicles and having testosterone concentrations in the male range. The clinical picture is variable and depends on the depth of the receptor alteration. At one extreme, there are cases of complete androgenic insensitivity (CAIS) with a female phenotype. At the other extreme, there is partial insensitivity (PAIS) that extends from the female phenotype, with or without genital ambiguity, to cases of infertile or undervirilized men, who have milder androgenic insensitivity. In female phenotypes, the testes are usually in an ectopic position and those located within the abdomen are at risk of malignancy, and therefore are usually removed. These are the most difficult cases to manage because apart from the need for gonadectomy followed by female hormonal therapy, there is a narrow vagina and a deep blind pouch that usually requires surgical correction to allow sexual activity. In this work, we present 5 cases of AIS recently seen in 2 clinical centers in Santiago and that illustrate the heterogeneity of presentation. In addition, we make an updated review of the diagnostic criteria, the most appropriate treatments, and the overall management of this condition.

Androgen insensitivity syndrome: a review

ABSTRACT Androgenic insensitivity syndrome is the most common cause of disorders of sexual differentiation in 46,XY individuals. It results from alterations in the androgen receptor gene, leading to a frame of hormonal resistance, which may present clinically under 3 phenotypes: complete (CAIS), partial (PAIS) or mild (MAIS). The androgen receptor gene has 8 exons and 3 domains, and allelic variants in this gene occur in all domains and exons, regardless of phenotype, providing a poor genotype - phenotype correlation in this syndrome. Typically, laboratory diagnosis is made through elevated levels of LH and testosterone, with little or no virilization. Treatment depends on the phenotype and social sex of the individual. Open issues in the management of androgen insensitivity syndromes includes decisions on sex assignment, timing of gonadectomy, fertility, physcological outcomes and genetic counseling.