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Steroidogenic factor 1 (SF-1) is an orphan nuclear receptor that plays key roles in endocrine development and function. Knockout mice lacking SF-1 have adrenal and gonadal agenesis, impaired gonadotropin expression, and structural abnormalities of the ventromedial hypothalamic nucleus. Previous studies have identified three human subjects with mutations in SF-1 causing adrenocortical insufficiency with varying degrees of gonadal dysfunction. We now describe a novel 8-bp microdeletion of SF-1, isolated from a 46, XY patient who presented with gonadal agenesis but normal adrenal function, which causes premature termination upstream of sequences encoding the activation function 2 domain. In cell transfection experiments, the mutated protein possessed no intrinsic transcriptional activity but rather inhibited the function of the wild-type protein in most cell types. To our knowledge, this is the first example of an apparent dominant-negative effect of a SF-1 mutation in humans. These findings, which define a SF-1 mutation that apparently differentially affects its transcriptional activity in vivo in the adrenal cortex and the gonads, may be relevant to the cohort of patients who present with 46, XY sex reversal but normal adrenal function.

In this review, we described the genes that encode an array of transcription factors, matrix proteins, hormones, enzymes and receptors that are expressed at multiple levels of the hypothalamic-pituitary-gonadal axis (HPG). In addition, we reported our experience in the identification and characterization of naturally occurring mutations in patients affected by HPG disorders, including hypergonadotropic hypogonadism and hypogonadotropic hypogonadism, isolated or associated with others pituitary hormonal deficiencies, and abnormalities of pubertal and sexual development. To date, fifteen distinct genes implicated with HPG axis development and function were identified: KAL, SF1, DAX1, LEPTIN, PC1, GnRH, GnRHR, HESX1, LHX3, PROP1, FSHR, LHR, LHb, FSHb and FGFR1. Most mutations identified in our cohort were described for the first time in literature and they frequently were associated with new clinical and hormonal aspects of the diseases. Characterization of the consequences of these mutations in in vitro studies have provided increased understanding of the structure and function of the proteins encoded by these genes. The combined clinical, hormonal and molecular diagnosis of HPG disorders have helped significantly to improve the knowledge and, consequently, the diagnosis and treatment of these patients.

SHOX is exclusively expressed in the developing distal limb bones of human embryos and in the first and second pharyngeal arches. It works as a promoter for linear growth and as a repressor of growth plate fusion. It was reported, recently, that SHOX overdosage and gonadal estrogen deficiency have led to tall stature due to continued growth. We report, in the present study, a female patient with 45,X/46,X, psu idic(X)(pter→q21::q21→pter) karyotype, tall stature, and hypergonadotrophic hypogonadism without Turner stigmas. She did not present breast development even after long term therapy with high estrogen doses. Fluorescence in situ hybridization depicted the presence of three copies of SHOX gene. Microsatellite studies showed paternal origin of der(X). Further studies in similarly affected patients will clarify if the absence of breast development, despite previous high-dose estrogen treatment, is associated to triple copy of SHOX gene. O gene SHOX é expresso, exclusivamente, no primeiro e no segundo arcos faríngeos, assim como nas extremidades dos ossos dos membros em embriões humanos. SHOX normalmente atua como um promotor para o crescimento linear e como um repressor do fechamento da placa de crescimento. Recentemente, foi descrito que o excesso da proteína SHOX associada à deficiência estrogênica gonadal leva à estatura alta devido ao contínuo crescimento. Neste estudo descrevemos uma paciente do sexo feminino com cariótipo 45,X/46,X,psu idic(X)(pter→q21::q21→pter), estatura alta, hipogonadismo hipergonadotrófico e sem estigmas de Turner. A paciente não apresentou desenvolvimento de mamas, mesmo depois do tratamento prolongado com altas doses de estrógenos. FISH evidenciou a presença de três cópias do SHOX. Estudo de microssatélites demonstrou a origem paterna do der(X). Estudos futuros em pacientes com semelhanças clínicas esclarecerão se a ausência de desenvolvimento de mamas, apesar do tratamento com altas doses de estrógenos, está associada à tripla cópia do SHOX.

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. Androgen insensitivity syndrome (AIS) is a rare X-linked disorder, caused by mutations in the androgen receptor gene (AR), associated with a variety of phenotypes in 46,XY individuals. We studied two 23 year-old twin-sisters with female social sex referred due to primary amenorrhea, who exhibited bilateral palpable gonads in the inguinal region and a 46,XY karyotype. The uterus was absent in pelvic sonograms. Basal LH levels were elevated (35 and 42U/L), with normal FSH (7.9 and 7.8U/L) and high testosterone levels (1330 and 1660ng/dl). The molecular analysis identified a missense mutation in exon 5 of AR gene that changed a proline to an alanine at position 766 of the protein. Proline 766 is a highly conserved amino acid in the AR of several species and is located in the androgen binding domain.

In most mammals, male development is triggered by the transient expression of the SRY gene, which initiates a cascade of gene interactions ultimately leading to the formation of a testis from the indifferent fetal gonad. Mutation studies have identified several genes essential for early gonadal development. We report here a molecular study of the SRY, DAX1, SF1 and WNT4 genes, mainly involved in sexual determination, in Brazilian 46,XX and 46,XY sex-reversed patients. The group of 46,XX sex-reversed patients consisted of thirteen 46,XX true hermaphrodites and four 46,XX males, and was examined for the presence of the SRY gene and for the loss of function (inactivating mutations and deletions) of DAX1 and WNT4 genes. In the second group consisting of thirty-three 46,XY sex-reversed patients we investigated the presence of inactivating mutations in the SRY and SF1 genes as well as the overexpression (duplication) of the DAX1 and WNT4 genes. The SRY gene was present in two 46,XX male patients and in none of the true hermaphrodites. Only one mutation, located outside homeobox domain of the 5' region of the HMG box of SRY (S18N), was identified in a patient with 46,XY sex reversal. A novel 8-bp microdeletion of the SF1 gene was identified in a 46,XY sex-reversed patient without adrenal insufficiency. The dosage of DAX1 and WNT4 was normal in the sex-reversed patients studied. We conclude that these genes are rarely involved in the etiology of male gonadal development in sex-reversed patients, a fact suggesting the presence of other genes in the sex determination cascade.