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Abstract: The term synaesthesia has been applied to a range of different sensory-perceptual and cognitive experiences, yet how these experiences are related to each other is not well understood. Not only are there disparate types of synaesthesia, but even within types there are vast individual differences in the way that stimuli induce synaesthesia and in the subjective synaesthetic experience. An investigation of the inheritance patterns of different types of synaesthesia is likely to elucidate whether a single underlying mechanism can explain all types. This study is the first to systematically survey all types of synaesthesia within a familial framework. We recruited 53 synaesthetes and 42% of these probands reported a first-degree relative with synaesthesia. We then directly contacted as many first-degree relatives as possible and collected complete data on synaesthetic status for all family members for 17 families. We found that different types of synaesthesia can occur within the same family and that the qualitative nature of the experience can differ between family members. Our findings strongly indicate that various types of synaesthesia are fundamentally related at the genetic level, but that the explicit associations and the individual differences between synaesthetes are influenced by other factors. Synaesthesia thus provides a good model to explore the interplay of all these factors in the development of cognitive traits in general. [Copyright &y& Elsevier]

The article discusses the inversion of the factor VIII gene (F8) causing haemophilia. According to initial hypothesis, homologous recombination between repeat int22h-1, in intron 22 of F8 and and one of the two duplicons, int22h-2 or int22h-3, in the reverse direction caused haemophilia A whereas at present, the duplicons are known to be inversely oriented in relation to each other forming imperfect palindrome with a central unique loop of 67.3 kb and arms of 50.5 kb.