Progressive cardiomyopathic lentiginosis.
Based mainly on the findings in eight patients and their families, a new syndrome is presented, consisting of multiple symmetrical lentigines and (mainly) left-sided obstructive cardiomyopathy, with associated growth retardation and at times slight intellectual impairment. The hypothesis is presented that the pathogenesis of the disorder is an extensive dysfunction of pigmentary and other elements of neural crest origin, and the signs and symptoms of the syndrome can be explained satis factorily by this. It is suggested that the obstructive cardiomyopathy is related to this defect, either primarily (because the neural crest contributes to heart structures) or secondarily (through the lentigines), and it is concluded that the disorder, which evidence suggests to be at least often dominantly inherited in an autosomal manner, has variable manifestations and, possibly, penetrance. Cases with lentigines, but without obstructive cardiomyopathy and, conversely, cases with obstructive cardiomyopathy but without lentigines, as well as some other clinical syndromes, may be pathogenetically related to the new syndrome. The hypothesis concerning the origin of the syndrome, which is supported by a number of hitherto unrelated observations, appears to be testable by biochemical studies of affected persons and by a careful investigation of their melanocytes and their melanosomes (see, e.g., Mishima, 1966) in normal and pigmented skin, and by detailed studies of the outflow cardiac tracts, their structure and metabolism.