Pertussis toxin "Bordetella" is that "B. pertussis" produces PT and the other species do not. "Bordetella parapertussis" shows the most similarity to "B. pertussis" and was therefore used for research determining the role of PT in causing the typical symptoms of whooping cough. Rat studies showed the development of paroxysmal coughing, a characteristic for whooping cough, occurred in rats infected with "B. pertussis". Rats infected with "B. parapertussis" or a PT-deficient mutant of "B. pertussis" did not show this symptom; neither of these two strains produced PT. A large group of bacterial exotoxins are referred to as "A/B toxins", in essence because
Meleda disease Meleda disease Meleda disease (MDM) or "mal de Meleda", also called Mljet disease, keratosis palmoplantaris and transgradiens of Siemens, (also known as "acral keratoderma", "mutilating palmoplantar keratoderma of the Gamborg-Nielsen type", "palmoplantar ectodermal dysplasia type VIII", and "palmoplantar keratoderma of the Norrbotten type") is an extremely rare autosomal recessive congenital skin disorder in which dry, thick patches of skin develop on the soles of the hands and feet, a condition known as palmoplantar hyperkeratosis. MDM is most common on the Dalmatian island of Mljet (or "Meleda"), thought to be because of a founder effect. It is of autosomal recessive inheritance.