[Corrected normal values for serum ACE by genotyping the deletion-/insertion-polymorphism of the ACE gene]

In sarcoidosis, serum ACE is widely recognised as a marker of disease activity. Since 1990 a deletion-/insertion polymorphism of the ACE gene is known and a correlation between the genotypes of this polymorphism and serum ACE levels has been observed. Homzygotes for the deletion allele (DD) have the highest levels and homozygotes for the insertion allele (II) the lowest. Heterozygote (DI) persons show intermediate levels. The extent of this influence varies in populations of different ethnic origin. In a large cohort of healthy individuals from North of Germany, genotype-based normal ranges for serum ACE were determined for the population of Germany for the first time.

In 262 healthy individuals the genotype of the ACE D/I gene polymorphism was determined from genomic DNA by a PCR method. In addition, in serum samples of all these individuals ACE level was measured with a kinetic test.

The genotype DD was found in 29.4 % of the individuals examined, the genotype DI in 49.6 % and the genotype II in 21.0 %, respectively. These results are similar to those found in previous investigations in other populations of Central European origin. The mean serum ACE levels (95 % confidence interval) in individuals with the genotypes DD, DI and II are 59.8 U/l (31.8 - 87.8), 47.7 U/l (18.6 - 76.8) and 32.2 U/l (13.7 - 50.7), respectively. Without taking the genotype into account, the average value is 48.0 U/l (15.0 - 80.9). Differences between all genotype groups are highly significant (p < 0.0001).

In sarcoidosis patients, the determination of this ACE gene polymorphism once in the course of the disease allows a better interpretation of the serum ACE levels measured.