Prenatal diagnostic procedures

A synopsis of prenatal diagnostic procedures is shown in Tables 2 and 3. 

Synopsis of available prenatal diagnostic procedures by ultrasound... 

According to ICH S6(R1), prenatal diagnostic procedures and growth measurements are no longer required, since birth weights of infants will be available. The use of ultrasound for the detection of malformations is not considered appropriate. 

Fibroblasts are typically grown from a small skin biopsy sample collected during an outpatient visit or as part of a planned surgical procedure following routine culturing techniques. Cell cultures may also be derived from umbilical cord or, for prenatal diagnostic purposes, from amniocytes obtained by amniocentesis. In our laboratory the analysis for each patient is performed in triplicate. 

Every prenatal evaluation should include which of the following diagnostic procedures ... 

When HCCAA is suspected because of clinical observations and/or family history, the diagnosis can easily be verified by demonstrating a low cerebrospinal fluid level of cystatin C (G10, J3) or the presence of the mutated cystatin C allele producing the Leu 68 Gin cystatin C variant (A6, PI). The first-mentioned procedure requires lumbar puncture and, to secure a stable level of cystatin C in the sample, the addition of a serine protease inhibitor, e.g., benzamidinium chloride, directly when the sample is drawn (Grubb, A., unpublished results). The PCR-based procedure is more robust, does not require lumbar puncture, and can be used for prenatal diagnosis and is therefore presently the preferable diagnostic method. 

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