The standard study material required for molecular genetic investigations, risk allele and risk profile determinations, as well as genotyping is 1 EDTA blood count vial. Alternatively, cheek mucosal swabs, tissue samples (in cell culture medium), or hair follicles can also be used to obtain DNA. In principle, the complete genetic information is present in all nucleated cells, and accessible for analysis by molecular genetic methods. Molecular genetics: Shipping is conducted by normal postage or by courier service. The DNA contained in the leucocytes is very stable, and therefore sample shipping times are of secondary importance. For analyses performed on RNA, however (e.g., translocation determinations in tumour diseases, analysis of virus.load etc.) special sampling and shipping conditions are to be observed, because RNA, in contrast to DNA, is rapidly degraded by ubiquitous RNAses. Cytogenetic investigations for postnatal diagnostics (indications include suspected Down or Klinefelter syndrome, condition after repeated abortions) require 5-10 ml sodium-heparinised whole blood. In the case of suspected chromosomal defect of an aborted foetus, shipment of placental or foetal tissue (e.g., umbilicus, skin or Fascia lata) in sterile physiological saline is recommended. For prenatal diagnostics, 15-20 ml of amniotic fluid or 10-30 mg of chorionic villi, removed under sterile conditions, are required. Cytogenetics: Shipping times are critical, as cell cultures must be set up in all cases. The study material should reach our laboratories within 48 hours. Cooling to 4ºC is advantageous, but not necessary. Samples should under no circumstances be frozen! Registration of study material by telephone assists us to plan.
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