LabPLUS is part of Auckland District Health Board
and provides medical laboratory testing
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MOLECULAR GENETICS TESTS - CYSTIC FIBROSIS |
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Background: Cystic fibrosis (CF) is a severe autosomal recessive disorder characterised by a variable degree of chronic obstructive lung disease and pancreatic enzyme insufficiency. The incidence of CF varies markedly among different populations. Among those of European, Caucasian ancestry, the incidence of the disease ranges from 1/1700 live births to 1/7700 (calculated carrier frequency 1/20 to 1/44), whereas it is extremely rare among Orientals and African blacks. To date, over 600 mutations have been described within the CF gene, which has been named cystic fibrosis transmembrane conductance regulator (CFTR). The most common mutation dF508, accounts for approximately 67% of the mutations world-wide and approximately 70 - 75% in a North American Caucasian population. Most of the remaining mutations are rather rare, except for the W1282X mutation which accounts for approximately 60% of the mutations in an Ashkenazi Jewish population. It is important to remember that this frequency differs among the different ethnic and racial groups. The distribution of other CF mutations has also been found to be heterogeneous among different populations. To obtain a better understanding of the distribution of the relatively common mutations in the world population, CF mutation screening data were collected for the most common mutations and submitted to the CF Genetic Analysis consortium. Studies in the general population have revealed that at least 15 - 20 mutations must be tested to detect 78% of obligate carriers. A recent survey suggested that at least 20 - 24 mutations may have to be screened to get the detection levels closer to 90. The only way (theoretically) to detect all possible mutations would be to sequence the entire gene, but the cost of that approach would be prohibitive for population screening. Different techniques have evolved since, to make the assay more efficient in terms of detecting more numbers of mutations. The Molecular Genetics laboratory offers a 31 mutation test which has been developed by PE Applied Biosystems. This is an assay system for the detection of mutations associated with CF incorporating Polymerase Chain Reaction (PCR), Oligonucleotide Ligation Assay (OLA) and Sequence-Coded Separation (SCS) using fluorescent technology. This single-tube multiplex DNA assay provides convenient, accurate and cost effective mutation detection. Analysis:
Blood: 3 x 4.0mL whole blood into EDTA tubes . Invert several times to mix. Forward within 24-48 hours at ambient temperature. Paediatric Samples: Minimum of 0.5mL whole blood in EDTA tubes. Prenatal Samples:
2 weeks once sample is received. Cost of test: CF31 - $283.34 Note: Prices excludes GST (12.5%) and may change without notice. Please click on a link below to view information about another specific test.
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