Pleiotropic effects of heterozygosity for the SERPINA1 Z allele in the UK Biobank

Homozygosity for the SERPINA1 Z allele causes alpha-1 antitrypsin deficiency, a rare condition that can cause lung and liver disease. However, the effects of Z allele heterozygosity on non-respiratory phenotypes, and on lung function in the general population, remain unclear. We conducted the largest population-based study to date to determine Z allele effects on >2,400 phenotypes using the UK Biobank study (N>303,353). We detected strong associations between heterozygosity and non-respiratory phenotypes including increased height, increased risk of gall bladder disease, reduced risk of heart disease and lower blood pressure, reduced risk of osteoarthritis and reduced bone mineral density, increased risk of headache and enlarged prostate, as well as with blood biomarkers of liver function. Heterozygosity was associated with higher lung function in non-smokers, but smoking appears to abolish this protective effect. Individuals heterozygous for the Z allele may therefore have altered risk of smoking-induced lung disease and other, non-respiratory conditions.