Karyotype

About: Karyotype is a research topic. Over the lifetime, 16278 publications have been published within this topic receiving 416409 citations.

Prader-Willi syndrome: Current understanding of cause and diagnosis

Abstract: Prader-Willi syndrome (PWS) is characterized by hypotonia, obesity, hypogonadism, short stature, small hands and feet, mental deficiency, a characteristic face, and an interstitial deletion of the proximal long arm of chromosome 15 in about one-half of the patients. The incidence is estimated to be about 1 in 25,000, and PWS is the most common syndromal cause of human obesity. DNA abnormalities, usually deletions or duplications of chromosome 15, have been identified in individuals with PWS with or without recognizable chromosome 15 deletions. Paternal origin of the chromosome 15 deletion by cytogenetic and DNA studies has been found in nearly all PWS individuals studied. No cytogenetic evidence for chromosome breakage has been identified, although an environmental cause (e.g., paternal hydrocarbon-exposed occupations) of the chromosome 15 abnormality has been proposed. PWS patients with the chromosome 15 deletion are more prone to hypopigmentation compared with PWS individuals with normal chromosomes, but no other clinical differences are consistently identified between those with and without the chromosome deletion. Anthropometric, dermatoglyphic, and other clinical findings indicate homogeneity of PWS patients with the chromosome deletion and heterogeneity of the nondeletion patients. A review of our current understanding of the major clinical, cytogenetic, and DNA findings is presented, and clinical manifestations and cytogenetic abnormalities are summarized from the literature.

ISCN 1991 : guidelines for cancer cytogenetics : supplement to An international system for human cytogenetic nomenclature : recommendations of the Standing Committee on Human Cytogenetic Nomenclature, Subcommittee on Cancer Cytogenetics

Abstract: General considerations modal number clones and clonal evolution order of chromosome abnormalities in the karyotype constitutional karyotype numerical chromosome abnormalities structural chromosome abnormalities specification of chromosome rearrangements marker chromosomes multiple copies of rearranged chromosomes uncertainty in chromosome or bank designation members of the ISCN Standing Committee and Subcommittee.

Cytogenetics of infertile men

Abstract: Chromosomally derived sterility has long been recognized. A review of the literature of somatic chromosome investigations in infertile males has shown that 13.7% of azoospermic males and 4.6% of oligozoospermic males have an abnormal karyotype. In the first group, sex chromosome abnormalities predominate (mainly 47,XXY), whereas in the latter, autosome anomalies (i.e. Robertsonian and reciprocal translocations) are the most frequent. A similar review on meiotic studies revealed that meiotic chromosome anomalies can explain male infertility in 4.3-40.4% of patients. Recently, fluorescent in-situ hybridization studies on spermatozoa from infertile men were published; it was suggested that both X-Y pairing and pairing of the autosomes were impaired, resulting in spermatogenic disruption. We investigated cytogenetically 694 infertile men with abnormal sperm parameters. More patients are needed for this research to investigate the relationship, if any, between the type of chromosome abnormality and its influence on the number, morphology and motility of spermatozoa. To be able to provide proper counselling for those couples whose male infertility can now be treated by intracytoplasmic sperm injection, it is suggested that clinical investigations should include mitotic and meiotic studies, an analysis of the chromosome content of individual spermatozoa and a DNA analysis of blood and spermatozoa to detect partially deleted Y chromosome material.