A free app (which is the third one of a set) providing an easy-to-use self-assessment quiz. It tests knowledge of the commonest inheritance mechanism or mode, in the UK, for each of 15 "single-gene" Mendelian and mitochondrial disorders that may be learned at college or university. After taking the quiz, a score is awarded & the correct answers are listed for each question that was answered incorrectly. Due to the overlap between X-linked recessive and X-linked dominant modes, these conditions