RESUMEN
OBJECTIVE: The objective of this study was to assess somatic and inherited androgen receptor gene mutations in families with only one affected individual. METHODS: Molecular genetic analysis of the androgen receptor gene in DNA derived from blood leukocytes from 30 families with single-strand conformation analysis, direct sequencing, and restriction fragment analysis was performed. RESULTS: In 22 families the mothers and all investigated grandmothers were heterozygous carriers. However, within the sisters and aunts, both heterozygous carriers and noncarriers were present. In eight families a de novo mutation was characterized. In three of these patients indication for somatic mosaicism was found. CONCLUSIONS: De novo mutations occur at a high rate within the androgen receptor gene (8 of 30 = 26.7%); a high proportion (3 of 8) arise after the zygote stage. Thus only direct analysis of the underlying mutation of the androgen receptor gene in the proband and his or her family can provide the basis for genetic counseling.
Asunto(s)
Síndrome de Resistencia Androgénica/genética , Mutación/genética , Receptores Androgénicos/genética , Cromosoma X/genética , Adulto , Niño , Análisis Mutacional de ADN , Femenino , Tamización de Portadores Genéticos , Ligamiento Genético , Heterocigoto , Humanos , Masculino , Mosaicismo , Linaje , Polimorfismo de Longitud del Fragmento de Restricción , Polimorfismo Conformacional Retorcido-SimpleRESUMEN
OBJECTIVE: Classification of severe hypospadias employing a broad array of diagnostic tools. Standardization of a diagnostic approach to children with hypospadias. Indentification of patients at risk of having malignancies and endocrine problems. DESIGN: Retrospective analysis of patients in a single-center study. SUBJECTS: Thirty-three patients with severe (scrotal or penoscrotal) hypospadias, aged 1 to 18 years. METHODS: Clinical assessment, ultrasonography, karyotyping, endocrine evaluation including adrenal steroid concentrations, sex hormone-binding globulin test for androgen sensitivity, human chorionic gonadotropin stimulation with determination of testosterone and dihydrotestosterone concentrations to exclude 5 alpha-reductase deficiency, and molecular genetic analysis of the androgen receptor gene and the 5 alpha-reductase gene. RESULTS: In 12 patients the cause was clarified. Diagnoses included Drash syndrome with Wilms tumor in infancy (3 patients), partial androgen insensitivity resulting from androgen receptor mutations (2), true hermaphroditism (2), chromosomal aberration (1), deficiency of antimüllerian hormone (1), gonadal dysgenesis (1), partial 5 alpha-reductase deficiency caused by a novel point mutation (1), and XX-male syndrome (1). Twelve patients had associated findings such as cardiac malformations (3 patients), rectal atresia (1), dilation of urinary tract (2), cystinuria (1), and others. CONCLUSIONS: Patients with severe hypospadias should be submitted to a standardized set of diagnostic procedures in infancy. A stepwise diagnostic study avoids unnecessary, invasive, and expensive testing. A high proportion of classified causes can be expected. Patients at risk of having malignancies or hormonal disorders must remain under close surveillance.