Tensor tympani- The tensor tympani is the larger of the two muscles of the auditory canal, the other being stapedius. The muscle functions to dampen down sounds such as chewing. It arises from the cartilaginous portion of the eustachian tube as well as the adjacent section of the greater wing of the sphenoid bone.
A nonsense mutation in the leptin gene that results in a stop codon and lack of leptin production was first observed in mice in 1950. In the mouse gene, arginine-105 is encoded by CGA and only requires one nucleotide change to create the stop codon TGA.
Mutations in PC-1, another peptide-processing enzyme, are also associated with obesity and increased leptin concentrations. The substrates of CPE and PC-1 that regulate weight and lead to obesity when these enzymes are defective are unknown. The tub gene product is highly expressed in the PVN, .