There are a number of named syndromes, for which there is now a small and growing literature outlining the ‘behavioural phenotype’, i.e. the particular profile/constellation of behaviours which is believed to be typical of the underlying, usually genetically determined, disorder. The body of evidence underpinning the particular behavioural and emotional styles and problems varies from one syndrome to another. Also, some of the syndromes have been relatively securely mapped on to the human genome, whereas several more, at the time of publication of this book, have no clear gene localization. For these reasons, the amount of information presented for each named syndrome in this chapter varies considerably. The syndromes will be described in alphabetical order. Most of these syndromes are known only by their ‘person's name label’. Although the policy in this respect varies, and is viewed differently, by different investigators, for purposes of coherence, syndromes named after one or other individual will be presented primarily in their ‘named’ variant. However, in the case of, for instance, neurofibromatosis and tuberous sclerosis, also known as von Recklinghausen disease and Bourneville disease, the former ‘names’ will be used, because these are now the ones most widely accepted.

The alphabetical listing may lead to some (hopefully slight) logical confusion, such as with tuberous sclerosis, neurofibromatosis and Ito's hypomelanosis, which are otherwise often grouped together in a section on ‘neurocutaneous disorders’.