TPM2 and Hypertonia: Cardiomyopathy-associated alteration in TPM2 gene expression in our spaceflight-exposed THP-1 cells (Fig. 4) mirrors the relationships between TPM2 genetic variant–affected muscle development and function changes that lead to a number of congenital myopathies, including nemaline myopathy, cap disease, distal arthrogryposis, and hypertonia (56, 57).