Complete Androgen Insensitivity Syndrome: A Rare Case of Prenatal Diagnosis / Síndrome de insensibilidade completa aos androgênios: um caso raro de diagnóstico pré-natal

Abstract With the widespread uptake of noninvasive prenatal testing (NIPT), a larger cohort of women has access to fetal chromosomal sex, which increases the potential to identify prenatal sex discordance. The prenatal diagnosis of androgen insensitivity syndrome (AIS) is an incidental and rare finding. We wish to present the diagnosis of a prenatal index case after NIPT of cell-free fetal DNA and mismatch between fetal sex and ultrasound phenotype. In this particular case, the molecular analysis of the androgen receptor (AR) gene showed the presence of a pathogenic mutation, not previously reported, consistent with complete androgen insensitivity syndrome. Carrier testing for the mother revealed the presence of the same variant, confirming maternal hemizygous inheritance. Identification of the molecular basis of these genetic conditions enables the preimplantation or prenatal diagnosis in future pregnancies.

Resumo Com a utilização generalizada de testes pré-natais não invasivos (TPNIs), uma crescente porção de mulheres tem acesso ao sexo cromossômico fetal, o que aumenta o potencial para identificar discordância sexual pré-natal. O diagnóstico pré-natal da síndrome de insensibilidade androgénica é um achado incidental e raro. Pretendemos apresentar um caso índice de diagnóstico pré-natal por meio de DNA fetal livre e incompatibilidade entre sexo fetal e fenótipo ecográfico. Neste caso particular, a análise molecular do gene do receptor de andrógenios (RA) revelou a presença de uma mutação patogênica, não relatada anteriormente, consistente com a síndrome de insensibilidade completa aos androgênios. A mãe revelou ser portadora da mesma variante, confirmando a hereditariedade hemizigótica. A identificação da base genética permite o diagnóstico pré-implantação ou pré-natal em futuras gestações.

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.

Síndrome de Insensibilidad Completa a Andrógenos (SICA): reporte de un caso clínico / Complete Androgen Insensitivity Syndrome (CAIS): report of a clinical case

INTRODUCTION: Complete Androgen Insensitivity Syndrome (CAIS) is a X-linked recessive disorder characterized by a complete resistance of the Androgen Receptor (AR) to androgens. As a result, affected individuals present complete female external genitalia, but are genetically male with a 46, XY karyotype. The typical presentation for this syndrome is either inguinal swellings in a new born or infant, or primary amenorrhoea in an adolescent. CAIS is commonly diagnosed in one of these clinical scenarios, although recently prenatal diagnosis has been reported. We present a case of a phenotypically female infant with an inguinal swelling, which was biopsied and exposed as testicular tissue, doing the diagnosis of CAIS. A review of the literature on this disorder is made.

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.

Genetic analysis of a family with complete androgen insensitivity syndrome.

Androgen insensitivity causes impaired embryonic sex differentiation leading to developmental failure of normal male external genitalia in 46 XY genetic men. It results from diminished or absent biological actions of androgens, which is mediated by the androgen receptor (AR) in both the embryo and secondary sexual development. Mutations in the AR located on the X chromosome are responsible for the disease. Almost 70% of affected individuals inherit the mutation from their carrier mother. We hereby report a 10‑year‑old girl with all the characteristics of complete androgen insensitivity syndrome (CAIS). Similar scenario was observed in 3 maternal aunts, Sequencing of the AR gene in all the family members revealed C 2754 to T transition in exon 6. It was concluded that the C 2754 to T transition rendered the AR incapable of both ligand‑binding and activating the transcription and was the cause of CAIS in the patient.

Complete androgen insensitivity syndrome

The incidence of Complete Androgen Insensitivity Syndrome [CAIS] is about 1 in 20.000. People with CAIS are normal appearing females, despite the presence of testes and a 46, XY chromosome constitution. We came across a case in which a 17 years old girl presented with the complaint of inguinal hernia and amenorrhea. Subsequent investigations were done revealing absence of female internal genitalia and the presence of abdominal mass, possibly testes. Syndrome has been linked to mutations in AR, the gene for the human Androgen Receptor, located at Xq11-12 leading to the insensitivity of the receptor to testosterone. Gonadectomy was performed and life long Hormone replacement therapy was advised

Síndrome de insensibilidade aos andrógenos: análise clínica, hormonal e molecular de 33 casos / Androgen insensitivity syndrome: clinical, hormonal and molecular analysis of 33 cases

A síndrome de insensibilidade aos andrógenos (AIS) é uma doença com herança ligada ao cromossomo X que afeta pacientes com cariótipo 46,XY, nos quais há prejuízo total (forma completa, CAIS) ou parcial (PAIS) do processo de virilização intra-útero devido à alteração funcional do receptor de andrógenos (AR). Apresentamos uma revisão da AIS e do AR com os dados clínicos, hormonais e moleculares de 33 casos. Analisamos a região codificadora do gene do AR em 33 pacientes de 21 famílias, com quadro clínico e hormonal sugestivo de AIS. Onze pacientes (9 famílias) com diagnóstico de CAIS e 22 pacientes (12 famílias) com diagnóstico de PAIS. Identificamos mutações no gene do receptor androgênico e a etiologia da síndrome de insensibilidade aos andrógenos em 86 por cento das 21 famílias estudadas: 100 por cento das famílias com insensibilidade completa aos andrógenos e 75 por cento das famílias com insensibilidade parcial aos andrógenos. Identificamos 9 mutações no AR descritas anteriormente na literatura (N705S, W741C, M742V, R752X, Y763C, R779W, M807V, R855C e R855H) e 7 mutações foram descritas pela primeira vez nesta casuística (S119X, T602P, L768V, R840S, I898F, P904R e IVS3 - 60 G>A).

Insensibilidade completa aos andrógenos em pacientes brasileiras causada pela mutação P766A no gene do receptor androgênico / Complete form of androgen insensitivity syndrome in brazilian patients due to P766A mutation in the androgen receptor

A síndrome de insensibilidade aos andrógenos é uma doença rara ligada ao X, causada por mutações no gene do receptor androgênico (AR), associada a uma variedade de fenótipos em indivíduos 46,XY. Avaliamos duas irmãs gêmeas de 23 anos com sexo social feminino encaminhadas por amenorréia primária, e que apresentavam gônadas palpáveis na região inguinal e cariótipo 46,XY. A ultra-sonografia pélvica não evidenciou útero. As dosagens basais revelaram concentrações elevadas de LH (35 e 42U/L), normais de FSH (7,9 e 7,8U/L) e altas de testosterona (1330 e 1660ng/dl). O estudo molecular identificou uma rara mutação missense no exon 5 do gene do AR com a troca de uma prolina por uma alanina na posição 766 da proteína. O aminoácido prolina 766 do AR é altamente conservado entre as espécies e situa-se em região correspondente ao domínio de ligação ao andrógeno.

An unusual case of haemophilia--a case report.

Haemophilia in a female is very rare. We report a case of haemophilia in a female with a male sex chromosome pattern.

Mutations of androgen receptor gene in Brazilian patients with male pseudohermaphroditism

We describe the identification of point mutations in the androgen receptor gene in five Brazilian patients with female assignment and behavior. The eight exons of the gene were amplified by the polymerase chain reaction (PCR) and analyzed for single-strand conformation polymorphism (SSCP) to detect the mutations. Direct sequencing of the mutant PCR products demonstrated single transitions in three of these cases: G > A in case 1, within exon C, changing codon 615 from Arg to His; G > A in case 2, within exon E, changing codon 752 from Arg to Gln, and C > T in case 3, within exon B, but without amino acid change

Ocorrência familiar da síndrome de feminizaçäo testicular: forma incompleta / Familiar occurence of testicular feminization syndrome

O presente estudo avaliou quatro irmäs, das quais três apresentavam quadro clínico de forma incompleta de feminizaçäo testicular. Ao exame físico detectou-se clitoromegalia, hirutismo, ausência de desenvolvimento mamário (paciente de 15 anos), vagina curta e de fundo cego, forma do corpo e distribuiçäo de pêlos tipicamente masculinos. A cromatina sexual foi negativa e o cariótiopo 46, XY. Duas primas em primeiro grau, do pai das pacientes, apresentavam o mesmo quadro clínico, quando foram estudads por Pizzaro e cols. em 1976

Dos casos de feminización testicular / Two cases of testicular feminization

Se presentan los casos de dos hermanos con síndrome de resistencia a los andrógenos en su variante de feminización testicular. Las edades al momento del diagnóstico fueron 14 y 17 años respectivamente; el más joven de los dos acudió a consulta por una tumoración en la región inguinal que resultó ser un testículo; el hermano fue estudiado porque al realizar su historia clínica se encontró que tenía amenorrea. Se describen los hallazgos físicos, los estudios psicológico y genético, y se explica el tratamiento que se les dio.