True about cystic fibrosis
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
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.
All India exam