True about cystic fibrosis
The immune reactive trypsin (I), used in diagnosis of those under 3 months can be checked on the Guthrie card. The sweat sodium concentrate on is the definitive test and this is diagnostic if on two tests the sodium is above 60mmol/l. False positive sweat tests are seen in Ectodermal Dysplasia.
The underlying defect in sodium channel function
The immune reactive trypsin (I) may be checked on the Guthrie card
In most cases the gene c defect is a loss of Valine at position 508 on chromosome 7
A sweat test with a sodium content above 40 mmol/l is diagnos c
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