Linkage of plasma alpha-L-fucosidase (FUCA2) and the plasminogen (PLG) system

Plasma fucosidase (FUCA2) was examined by means of a technique using p-nitrophenyl-alpha-L-fucopyranoside as substrate. The material consisted of normal Danish families, including 1,672 unrelated persons (parents). In this material the low activity allele frequency was found to be plow = 0.286 which agrees with earlier studies in European populations. The allele frequencies did not differ significantly between the sexes. Segregation ratios agreed with the hypothesis that 'low' is due to an autosomal recessive allele. Our results give a strong indication of linkage for FUCA2-PLG (z = 7.37 theta = 0.12) in males, and the linkage may be considered as formally demonstrated. The PLG-system as judged from our indication of linkage with GC (z = 2.35, theta = 0.30 in males) is then possibly located on chromosome 4p (Eiberg et al. 1981).