Human surfactant protein-A gene locus for genetic studies in the Finnish population

Lung surfactant lowers the surface tension but surfactant proteins also hav e other functions. Surfactant protein A (SP-A) has a well-defined role in i nnate immunity. The gene locus for human SP-A genes is in chromosome 10q21 through q24 and consists of two highly homologous functional SP-A genes (SP -AI and SP-A2) and a pseudogene. Several alleles that differ by a single am ino acid have been identified for both SP-A genes. The SP-A gene locus has been shown to be sufficiently polymorphic for genetic studies in the Americ an population. In this study, we analysed the SP-A allele frequencies in a Finnish population (n = 790) and found them to differ from the frequencies observed in US. Furthermore, we describe several new alleles for both SP-A genes. The heterozygosity indices and polymorphism information content valu es ranged between 0.50-0.62 indicating that SP-A gene locus is polymorphic enough for studies associating the locus with pulmonary diseases.