Familial disorder of sex determination in seven individuals from three related sibships

In humans, the sex of an individual is determined by the Y-chromosome-related SRY gene, which causes the differentiation of the undifferentiated gonads into testicular tissue. True hermaphrodites without a Y chromosome and XX males represent a sex determination error in which testicular tissue develops despite the absence of the SRY gene. Familial forms of XX true hermaphrodites and XX males exist in the literature, which also contains the two forms co-existing in the same family. In this report, we present a large family with seven affected individuals with phenotypes ranging from XX male to XX true hermaphrodite with predominance of female characteristics. We suggest that XX maleness and XX true hermaphroditism represent a continuum of the same disorder. We speculate on the mode of inheritance of this disorder in this particular family.