The marked difference between black and white females in cancellous vertebral bone density occurs during a relatively brief period late in puberty. Metabolic and hormonal events related to the achievement of sexual maturity during adolescence may be important determinants of racial differences in bone mass in women.

The role of HLA class II alleles in genetic predisposition to insulin dependent diabetes mellitus (IDDM) was examined by PCR/oligonucleotide probe typing of 42 Mexican-American IDDM families derived from Hispanic Caucasians and Native Americans. All high risk haplotypes (HLA-DR3 and DR4) were of European origin while the most strongly protective haplotype (DRB1*1402) was Native American. Of the 16 DR-DQ DR4 haplotypes identified, only those bearing DQB1*0302 conferred risk; the DRB1 allele, however, also markedly influenced IDDM risk. The general pattern of neutral and protective haplotypes indicates that the presence of Asp-57 in the HLA-DQ beta chain does not confer IDDM protection per se and indicates that both DRB1 and DQB1 influence IDDM susceptibility as well as protection.

\s=b\Endocrine function evaluations in 16 patients with \g=b\-thalassemia indicate that hypogonadotropic hypogonadism, hypoparathyroidism, and reduced adrenocorticotropic hormone reserve occur frequently, whereas reduced growth hormone and thyroid reserve are less common manifestations. Hemosiderosis-induced damage of the endocrine glands seems to be the main cause for endocrine dysfunction in the patients studied.