The 47, XXX karyotype has a frequency of 1 in 1000 female newborns. However, this karyotype is not usually suspected at birth or childhood. These patients are usually diagnosed during adulthood when they develop premature ovarian failure or infertility, because the early phenotype doesn´t have any specific features. The study describes four cases and the clinical variability of the 47, XXX karyotype.

El síndrome 47, XXX se debe a un cromosoma extra del par sexual; su incidencia es de 1 en 1000 recién nacidas vivas. Sin embargo, este síndrome no suele sospecharse al nacimiento ni en la infancia. Muchas de estas pacientes son diagnosticadas durante la edad adulta por falla ovárica precoz o esterilidad, debido a la falta de características clínicas específicas. Este trabajo describe cuatro casos de pacientes 47, XXX y su variabilidad fenotípica.

The location of 18S and 5S rDNA sites was determined in eight species and populations of the fish genus Triportheus by using fluorescent in situ hybridization (FISH). The males and females of all species had 2n = 52 chromosomes and a ZZ/ZW sex chromosome system. A single 18S rDNA site that was roughly equivalent to an Ag-NOR was detected on the short arms of a submetacentric pair in nearly all species, and up to two additional sites were also observed in some species. In addition, another 18S rDNA cluster was identified in a distal region on the long arms of the W chromosome; this finding corroborated previous evidence that this cluster would be a shared feature amongst Triportheus species. In T. angulatus, a heterozygotic paracentric inversion involving the short arms of one homolog of a metacentric pair was associated with NORs. The 5S rDNA sites were located on the short arms of a single submetacentric chromosomal pair, close to the centromeres, except in T. auritus, which had up to ten 5S rDNA sites. The 18S and 5S rDNA sites were co-localized and adjacent on the short arms of a chromosomal pair in two populations of T. nematurus. Although all Triportheus species have a similar karyotypic macrostructure, the results of this work show that in some species ribosomal genes may serve as species-specific markers when used in conjunction with other putatively synapomorphic features.