The frequency of large mutations was determined in 131 Brazilian patients with different clinical forms of 21-hydroxylase deficiency, belonging to 116 families. DNA samples were examined by Southern ...blotting hybridization with genomic CYP21 and C4cDNA probes after TaqI and BglII restriction. Large gene conversions were found in 6.6% and CYP21B deletions in 4.4% of the alleles. The breakpoint in these hybrid genes occurred after exon 3 in 92% of the alleles. All rearrangements involving CYP21B gene occurred in the heterozygous form, except in a patient with simple virilizing form who presented homozygous CYP21B deletion. Our data showed that in these Brazilian patients, CYP21B deletions were less frequent than in most of the large series previously reported.
Male sexual precocity is defined as the development of secondary sexual characteristics before 9 years of age. It can be classified as gonadotropin-dependent precocious puberty (GnDP) or ...gonadotropin-independent precocious puberty (GnIP) and sometimes the differential diagnosis between these entities is difficult. To determine whether long-acting GnRH agonists (GnRH-a) are effective in differential diagnosis of male precocious puberty, we measured gonadotropins and testosterone levels 30 days after a single administration of depot GnRH-a (triptorelin, gosereline or leuprolide) in 10 boys with sexual precocity of different etiologies. Testosterone levels 30 days after depot GnRH-a were in the prepubertal range in patients with GnDP but not in GnIP. We conclude that measurement of testosterone levels 30 days after long-acting GnRH-a is effective in the differential diagnosis of male sexual precocity.
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