Defects in seven genes encoding sarcomere proteins have been shown to cause hypertrophic cardiomyopathy. To date, only one study reporting defects in the cardiac troponin I gene associated with hypertrophic cardiomyopathy has been published, and the proportion of hypertrophic cardiomyopathy cases caused by defects in this gene is unknown. Therefore, the authors screened 37 unrelated Finnish patients with hypertrophic cardiomyopathy for variants in the cardiac troponin I gene. Exons 1-8 of the troponin I gene were screened with the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) method. Five different variants (four intron variants and one silent exon variant) were found. Most variants were also present in control samples and none of the variants co-segregated with the disease in families. The results of the present study indicate that defects in the cardiac troponin I gene do not cause hypertrophic cardiomyopathy in patients from Eastern Finland.