Eustachian Tube Growth and Development: Anatomy/Function. Protocol Description. This study measures Eustachian tube function and facial growth over time in three groups of children: one with recurrent ear infections, one with chronic middle ear fluid, and one with little past history of otitis media.
Causes of Kartagener syndrome. Kartagener syndrome is caused by a mutation in the DNAI1 gene, which makes a cellular protein required for normal functioning cilia (cilia line the respiratory tract) and sperm motility.
The HTT mutation that causes Huntington disease involves a DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks (cytosine, adenine, and guanine) that appear multiple times in a row. Normally, the CAG segment is repeated 10 to 35 times within the gene. In people with Huntington disease, the CAG segment is repeated 36 to more than 120 times. People with 36 to 39 CAG repeats may or may not develop the signs and symptoms of Huntington disease, while people with 40 or more repeats almost always develop the disorder.