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Sertoli cells are the most active cell population in the testis during infancy and childhood. In these periods of life, hypogonadism can only be evidenced without stimulation tests, if Sertoli cell function is assessed. AMH is a useful marker of prepubertal Sertoli cell activity and number. Serum AMH is high from fetal life until mid-puberty. Testicular AMH production increases in response to FSH and is potently inhibited by androgens. Serum AMH is undetectable in anorchidic patients. In primary or central hypogonadism affecting the whole gonad and established in fetal life or childhood, serum AMH is low. Conversely, when hypogonadism affects only Leydig cells (e.g. LHβ mutations, LH/CG receptor or steroidogenic enzyme defects), serum AMH is normal or high. In pubertal males with central hypogonadism, AMH is low for Tanner stage (reflecting lack of FSH stimulus), but high for the age (indicating lack of testosterone inhibitory effect). Treatment with FSH provokes an increase in serum AMH, whereas hCG administration increases testosterone levels, which downregulate AMH. In conclusion, assessment of serum AMH is helpful to evaluate gonadal function, without the need for stimulation tests, and guides etiological diagnosis of pediatric male hypogonadism. Furthermore, serum AMH is an excellent marker of FSH and androgen action on the testis. As células de Sertoli são a população de células mais ativa nos testículos durante a primeira e segunda infância. Neste período, o hipogonadismo só pode ser evidenciado sem o uso de testes estimulatórios se a função das células de Sertoli for avaliada. O AMH é um marcador útil do número e da atividade das células de Sertoli no período pré-puberal. A concentração sérica de AMH é alta da metade da vida fetal até a metade da puberdade. A produção de AMH pelos testículos aumenta em resposta ao FSH e é potencialmente inibida por androgênios. O AMH sérico não é detectável em pacientes anorquídicos. No hipogonadismo central ou primário afetando a gônada inteira, ou estabelecido na vida fetal ou infância, a concentração de AMH sérica é baixa. Por outro lado, quando o hipogonadismo afeta apenas as células de Leydig (por exemplo, nas mutações, LHβ, defeitos do receptor de LH/CG ou das enzimas esteroidogênicas), a concentração de AMH sérico é normal ou alta. Em meninos púberes com hipogonadismo central, a concentração de AMH é baixa para o estágio na escala de Tanner (refletindo a falta de estímulo pelo FSH), mas alta para a idade (indicando a falta do efeito inibidor da testosterona). O tratamento com FSH provoca um aumento do AMH sérico, enquanto a administração de hCG aumenta os níveis de testosterona, que fazem a downregulation do AMH. Em conclusão, a concentração sérica de AMH é útil na avaliação da função gonadal, excluindo a necessidade de testes estimulatórios, e direciona o diagnóstico etiológico do hipogonadismo pediátrico masculino. Além disso, o AMH sérico é um marcador excelente da ação do FSH e dos androgênios nos testículos.

Context Larger studies on outcomes in males with 45,X/46,XY mosaicism are rare. Objective To compare health outcomes in males with 45,X/46,XY diagnosed as a result of either genital abnormalities at birth or nongenital reasons later in life. Design A retrospective, multicenter study. Setting Sixteen tertiary centers. Patients or Other Participants Sixty-three males older than 13 years with 45,X/46,XY mosaicism. Main Outcome Measures Health outcomes, such as genital phenotype, gonadal function, growth, comorbidities, fertility, and gonadal histology, including risk of neoplasia. Results Thirty-five patients were in the genital group and 28 in the nongenital. Eighty percent of all patients experienced spontaneous pubertal onset, significantly more in the nongenital group (P = 0.023). Patients were significantly shorter in the genital group with median adult heights of 156.7 cm and 164.5 cm, respectively (P = 0.016). Twenty-seven percent of patients received recombinant human GH. Forty-four patients had gonadal histology evaluated. Germ cells were detected in 42%. Neoplasia in situ was found in five patients. Twenty-five percent had focal spermatogenesis, and another 25.0% had arrested spermatogenesis. Fourteen out of 17 (82%) with semen analyses were azoospermic; three had motile sperm. Conclusion Patients diagnosed as a result of genital abnormalities have poorer health outcomes than those diagnosed as a result of nongenital reasons. Most patients, however, have relatively good endocrine gonadal function, but most are also short statured. Patients have a risk of gonadal neoplasia, and most are azoospermic, but almost one-half of patients has germ cells present histologically and up to one-quarter has focal spermatogenesis, providing hope for fertility treatment options.