BACKGROUND: Phospholamban is an endogenous sarcoplasmic reticulum calcium ATPase 
inhibitor with a regulatory effect on cardiac contraction/relaxation coupling. 
Mutations in the phospholamban gene (PLN) have been associated with primary 
cardiomyopathies.
AIMS: To screen for PLN mutations in our population of patients with primary 
cardiomyopathies and to perform functional analysis of the mutations identified.
METHODS: We performed SSCP mutational screening and DNA sequencing of the PLN 
gene in 186 patients with either hypertrophic or dilated cardiomyopathy. To 
study promoter strength we constructed reporter plasmids containing the 
luciferase gene and performed transient transfection analysis in C6 and C2C12 
cell lines.
RESULTS: The PLN -42 C>G mutation was found in one patient with late onset 
familial apical hypertrophic cardiomyopathy. This mutation decreased 
phospholamban promoter activity by 43% and 47%, in C6 and C2C12 cell lines 
respectively. One son had mild apical hypertrophic cardiomyopathy and carried 
the mutation, another son with normal ECG and echocardiogram also had the 
mutation.
CONCLUSION: The PLN -42 C>G mutation is associated with a benign form of apical 
hypertrophic cardiomyopathy in this family, though the presence of a healthy 
adult carrier suggests that other genetic and environmental factors could be 
involved. Otherwise, mutations in the PLN gene are not a frequent cause of 
cardiomyopathies in our population.