ABSTRACT
Familial aggregation of lung function has been observed in individuals with AAT deficiency. Silverman and colleagues158
investigated quantitative spirometric phenotypes in 82 PI MZ first-degree relatives of PI Z individuals with and without airflow obstruction. A trend for lower FEV1 was observed in the PI MZ relatives of PI Z individuals with FEV1 65 percent of predicted when compared with the FEV1 of PI MZ relatives of PI Z individuals with FEV1 65 percent of predicted (93 versus 101 percent predicted). FEV1 measures were lower in parents of PI Z individuals in the lower lung function category compared to parents of PI Z individuals with higher lung function (75 versus 95 percent predicted).158 In addition, segregation analysis on 44 nuclear families with AAT-deficient individuals suggested the presence of additional genetic factors that contribute to the phenotypic manifestations of disease.159
