A dysfunctional Eustachian tube that is always open is called a patulous Eustachian tube. Patients with this rare condition are plagued by chronic ear infections. A much more common problem is a failure of the Eustachian tube to effectively regulate air pressure.
A frameshift mutation (also called a framing error or a reading frame shift) is a genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three.he frameshift mutation will also alter the first stop codon (UAA, UGA or UAG) encountered in the sequence. The polypeptide being created could be abnormally short or abnormally long, and will most likely not be functional.
When mutations occur in multiples of three, however, another amino acid may be produced, but frameshift mutations do not occur because the reading frame is not altered. Tay-Sachs disease occurs when the enzyme hexosaminidase A, which breaks down fatty acids in the brain, does not function properly.