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Chromosome trisomies are considered alterations in the chromosome number or structure. A trisomy is therefore a type of polysomy in which there are three chromosome copies, instead of the normal two. A trisomy is considered an aneuploidy or abnormal number of chromosomes. There are two different trisomy types; Full trisomy\" where an entire extra chromosome has been copied. \"Partial trisomy\" means that there is an extra copy of part of a chromosome. Depending on the chromosome, a trisomy is named as “Autosomal trisomies\" (trisomies of the non-sex chromosomes) and \"Sex-chromosome trisomies.\" In this study both Autosomal and Sex-chromosome trisomies are described in differents patients, depending on the affected chromosome. Among 4617 chromosomal studies performed during 19 years (from 1992 to 2011), at Hospital Para el Niño Poblano in México, 34.6% (1596 patients) had chromosomal alterations. Among these studies population, a male and female pediatric patients are described, with different chromosome trisomies, were chromosome changes are classified as structural or numeric alterations. All trisomies patients were described in this study analyzing their phonotypical and clinical features, medical treatments and prognosis.

The autosomic alteration due to a ring formation is a rare aberration of either chromosome 13 and 18 which is in relation with phenotipic malformations, neurologic problems and genital abnormalities. Two clinical polymalformed cases with skull treboliform dismorfies with early seizures and malformed genitals with micropenis is presented from four of the total patients found in this study. Among chromosomic alterations, the ring of autosomic chromosome 13 and 18 are not frequent, the main phenotipical alterations in this study are in relation to neurological, genital and craniofacial malformations. Taking in consideration that mutations or chromosome aberrations are alterations in the chromosome number or structure. They are mainly considered due to gametogenesis inborn error (meiosis) or during the zygote first cellular divisions. All these alterations might be observed during metaphase from the cellular cycle, where DNA loses are seen due to DNA repair processes deficiency o total absence, among others. 4617 chromosomal studies were performed at Hospital Para El Nino Poblano (Pediatric Hospital) in Mexico (from 1992 to 2011) were 34.6% (1596 patients) showed different chromosomal alterations and only two patients showed ring chromosome aberrations. These chromosome changes are classified as structural alterations. Both pediatric patients with these genetic diseases are described in this study analyzing their clinical characteristics, medical or surgical treatments according to the phenotypic alterations.

The majority of de novo structural chromosome aberrations in fetuses and newborns are considered being of cells of mammals for DNA damage during gametogenesis. 4617 chromosomal studies performed during 19 years (from 1992 to 2011), at Hospital Para El Niño Poblano in México, a total of 1596 patients showe positive for DNA aberrations. Among these studies population, 0.23% (11) chromosome translocations were observed. From this data, two male pediatric patients are described, with 1;4 and 6;9 chromosome translocations. Chromosome changes are classified as structural or numeric alterations respectively, and abnormal cell development has been associated with these two specific chromosomal translocations. The patients in this study were then analyzed and compared both hematological and compared to their clinical features.

Chromosome aberrations are considered changes in the chromosome number or structure. The etiology factor is due to gametogenesis inborn error (meiosis) or during the zygote first cellular divisions. It might occurs during metaphase from the cellular cycle, where DNA loses are seen (clastogenic processes) due to DNA repair processes deficiency o total absence, among others. Six genetic patients associated to chromosome 4 aberration were analyzed; three Wolf-Hirschhorn syndrome patients, a deletion of long arm 4 chromosome and two 1;4 and 3;4 chromosome translocations among 4617 Karyotype studies performed during 19 years period of time (from 1992 to 2011) at a Pediatric Hospital in Mexico. These chromosome changes are classified as structural alterations where these six patients from different families were chosen to evaluate their clinical characteristics, medical or surgical treatments according to their different genetic aberration.