SFTPA1 and newborn respiratory distress syndrome: Interestingly, the SNPs that determine the SP-A1 6A4 and SP-A2 1A5 haplotypes (i.e., those which were found to be associated with RDS in the present study) result in amino acid substitutions within the collagen-like and the carbohydrate recognition domain of the SP-A protein [25], two regions of critical importance for optimal protein function [25].