PubMed · 13873739
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W M BROWN. 1961. Human chromosome abnormalities.. https://pubmed.ncbi.nlm.nih.gov/13873739/
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Extra structurally abnormal chromosomes (ESACs) and cryptic rearrangements are often associated with mental retardation and phenotypic abnormalities. In some cases their characterisation, using standard cytogenetic techniques and fluorescence in situ hybridization (FISH), is difficult and time consuming, where a fast and accurate identification is essential, especially when such chromosomal aberrations are found in prenatal diagnosis. A recent molecular technique, spectral karyotyping (SKY), based on the spectral signature of 24 chromosome-specific painting probes labelled with different combinations of five fluorochromes, allows the simultaneous visualisation of all human chromosomes in different colours. We used SKY analysis on 14 cases with rare ESACs or cryptic unbalanced rearrangements found at pre- or postnatal diagnosis. SKY analysis permitted the classification of chromosome rearrangements in all 14 cases analysed in combination with FISH analysis.
Preimplantation genetic diagnosis (PGD) was introduced at the beginning of the 1990s as an alternative to prenatal diagnosis, to prevent termination of pregnancy in couples with a high risk for offspring affected by a sex-linked genetic disease. At that time, embryos obtained in vitro were tested to ascertain their sex, and only female embryos were transferred. Since then, techniques for genetic analysis at the single-cell level, involving assessment of first and second polar bodies from oocytes or blastomeres from cleavage-stage embryos, have evolved. Fluorescence in-situ hybridisation (FISH) has been introduced for the analysis of chromosomes and PCR for the analysis of genes in cases of monogenic diseases. In-vitro culture of embryos has also improved through the use of sequential media. Here, we provide an overview of indications for, and techniques used in, PGD, and discuss results obtained with the technique and outcomes of pregnancies. A brief review of new technologies is also included.
Teratomas are uncommon neoplasms comprised of mixed dermal elements derived from the three germ cell layers. Historically, teratomas were attributed to demons, sexual misconduct, and abnormal fertilization. They attract attention because of their bizarre histology and gross appearance. While the majority of teratomas present congenitally in the sacrococcygeal region, within the ovaries of adolescent females and within the testes of young men, they have been identified throughout the body. Extragonadal teratomas tend to occur in midline structures as the anterior mediastinum, retroperitoneum, sacrococcygeal region, and pineal gland. Retroperitoneal teratomas represent only 1-11% of primary retroperitoneal tumors. Incidence is bimodal with peaks in the first 6 months of life and in early adulthood. Due to their location, they are usually identified only after they have grown to huge proportions. There is a 25% chance of malignancy. Surgical resection remains the mainstay of therapy and is required for definitive diagnosis. This article reviews the literature on the histopathology, classification, genetic abnormalities, and theories of origin of teratomas as well as the presentation, diagnosis, and management of retroperitoneal teratomas.