MYBPC1

The MYBPC1 gene provides instructions for making one version of a protein called myosin binding protein C. Several versions of myosin binding protein C are produced from different genes; these proteins are found in muscles used for movement (skeletal muscles) and in heart (cardiac) muscle. The version produced from the MYBPC1 gene, which is known as the slow skeletal isoform, is found primarily in skeletal muscles.

The slow isoform of myosin binding protein C is active during the development of skeletal muscles. Researchers believe that this protein helps regulate the tensing of muscle fibers (muscle contraction). Myosin binding protein C interacts with other muscle proteins, including myosin, actin, and titin. These proteins play essential roles in muscle cell structures called sarcomeres, which generate the mechanical force needed for muscles to contract. Studies suggest that myosin binding protein C contributes to the stability and maintenance of sarcomeres.

distal arthrogryposis type 1 - caused by mutations in the MYBPC1 gene

At least one mutation in the MYBPC1 gene has been found to cause distal arthrogryposis type 1, a disorder characterized by joint deformities (contractures) in the hands and feet. The mutation changes a single protein building block (amino acid) in the slow isoform of myosin binding protein C. Specifically, the mutation replaces the amino acid tryptophan with the amino acid arginine at protein position 236 (written as Trp236Arg or W236R). It is unclear how the defective protein leads to contractures in people with distal arthrogryposis type 1, or why the joint problems are typically limited to the hands and feet. However, researchers speculate that contractures may be related to problems with muscle contraction that limit the movement of joints before birth.