delta-Aminolevulinatedehydrase: synteny with ABO-AK1-ORM (and assignment to chromosome 9).

A material comprising 846 normal families from the Copenhagen area (fam. no. 604-1505) was tested for delta-aminolevulinatedehydrogenase. Among the 1697 unrelated individuals (parents), the gene frequencies were 0.9378 for ALADH 1 and 0.0622 for ALADH 2. The distribution of phenotypes and the segregation ratios did not deviate significantly from the expected values. Linkage analysis was carried out for markers on chromosome 9, following up a hint of ALADH-ORM linkage in part of the material. This was confirmed, and the most likely sequence, as judged from male theta values, was found to be ABO-AK1-ALADH-ORM. The theta and z values were as follows: ABO-AK1 (theta = 0.13, z = 6.27), ABO-ALADH (theta = 0.21, z = 5.38), ABO-ORM (theta = 0.27, z = 5.06), AK1-ORM (theta = 0.17, z = 1.63), ALADH-ORM (theta = 0.13, z = 7.05) and AK1-ALADH (theta = 0.11, z = 2.45).