RESUMO
Cytogenetic analysis of patients with Ullrich-Turner syndrome (UTS) may fail to detect low levels of Y chromosome mosaicism or Y-derived marker chromosomes. More sensitive polymerase chain reaction (PCR)-based tests have been developed; however, applicability of these data to prognosis of virilization and gonadoblastoma development has not been investigated adequately. We used a multiplex PCR-based method to detect two Y-specific sequences, SRY and AMGLY. Thirteen patients with UTS without cytogenetically detected Y chromosomes were studied. Y-specific sequences were detected in 5 patients by multiplex PCR. A cryptic translocation involving the Y chromosome was found in one patient with severe virilization of external genitalia and a male phenotype. Y chromosomal mosaicism was detected in peripheral blood and in both gonads of one patient, and only in the left gonad of another patient. Existence of a Y-derived marker was demonstrated in 2 patients, one of whom had no testicular tissue or virilization. Consistent with previous reports, we conclude that PCR is more sensitive than classical cytogenetic analysis and detects patients with Y-specific sequences in blood cells. However, the absence of Y-specific material in blood is not a sufficient reason to reject surgical treatment in case of virilization.
Assuntos
Proteínas de Ligação a DNA/química , Proteínas Nucleares , Reação em Cadeia da Polimerase/métodos , Fatores de Transcrição , Síndrome de Turner/genética , Cromossomo Y , Adolescente , Amelogenina , Criança , DNA/sangue , Proteínas de Ligação a DNA/genética , Proteínas do Esmalte Dentário/genética , Feminino , Gonadoblastoma/etiologia , Gonadoblastoma/genética , Gônadas , Humanos , Cariotipagem , Masculino , Mosaicismo , Fenótipo , Proteína da Região Y Determinante do Sexo , Translocação Genética , Síndrome de Turner/sangue , Síndrome de Turner/complicações , Virilismo/etiologia , Virilismo/genética , Cromossomo XRESUMO
Different hypotheses for genetic control of sexual differentiation in humans are discussed. Information on structure and manifestation of genes determining development of internal and external male genitals is considered. The process of discovering the gene responsible for differentiation of the indifferent fetal gonad into testes is described. The etiological problems of sexual development disorders are considered on the basis of knowledge obtained by modern molecular and genetic methods.
