真性半陰陽の細胞遺伝学的検索

性染色体構成と性腺および導管系の分化

抄録

Eleven cases of true hermaphrodites were investigated with special reference to the relationship between differentiation of gonads and development of sexual duct systems. On most of them were performed studies of the sex chromatin, fluorescent body and chromosomal analysis. Also, reported cases in Japan as well as in foreign countries were collected and reviewed.
Chromosomal analysis on 9 cases revealed chromosomal constitutions of 46, XX in 3 cases, 46, XY in 4 and 46, XX/46, XY in 2.
Four cases out of 5 patients with a testis at one side and an ovary at the opposite showed Y-bearing chromosomal constitutions. Most of reported cases with a similar type of gonadal developement as the above mentioned were proved to have Y chromosome in their stem cells.
Analysis of chromosomes in myelocytes and lymphocytes from a patient with 46, XX/46, XY revealed an interesting result. Twenty-one myelocytes out of 24 had chromosomal constitution of 46, XY and only 3 had 46, XX, whereas almost all of lymphocytes investigated after culture of peripheral blood had 46, XX constitution. It may be suggested from the above finding that cell populations are different from one tissue to another and may influence the differentiation of the primordial gonad toward a testis or ovary. It was another interesting finding that the fluorescent body was observed in 19% of lymphocytes from the patient mentioned above. The observation indicates the importance of examining Barr body as well as fluorescent body on more than two kinds of tissues, because native cells without cell-culture can be utilized for the examinations.
Six true hermaphrodites investigated for both Barr and fluorescent bodies consisted of two of 46, XX, 46, XY and 46, XX/46, XY, respectively. Both bodies were positive in each case with mosaicism 46, XX/ 46, XY, although their frequencies were at lower percentage than normal female or male. On the other hand, only a few Barr or fluorescent bodies were recognized in each case of 46, XY or 46, XX, respectively. It is difficult to decide whether the above results were caused by an unrecognized mosaicism or not.
From the observations of true hermaphrodites and XX-males, there has been raised an assumption that a sex-determining factor may locate on one of autosomes to which Y chromosome may affect as a regulating factor. This assumption, however, appears not sufficient to explain the differentiation of the ovarian tissue in the case of 46, XY.
Testes in the foetus stimulate the differentiation and development of the Wolflian duct and suppress the Mullerian duct. The former function appears to be controlled by one of androgens secreted from the foetal testis. From the observation of clinical cases and animal experiments, the latter function seems to be closely related to the chromosomal constitution of cells composing the ductal tissue, while this function must be mediated by a chemical messenger produced from the foetal testis.