A total of 5,020 individuals living in two southern Brazilian states were screened in relation to albumin types; two variants were found, in Passo Fundo (Nagasaki 2) and Vera Cruz (Tradate 2). Another variant, detected in the northeast, was identified as Porto Alegre 2, which also occurs in other places in Brazil, as well as in India, Pakistan, and Turkey. The results were integrated with those obtained in other studies in South America, yielding a total of 16,941 Amerindians and 23,839 non-Indian subjects. Molecular and physiological studies performed in some of the variants suggested clues to explain the restricted distribution of albumin Yanomama 2 and the widespread occurrence of albumin Maku. Am. J. Hum. Biol. 11: 359-366, 1999. © 1999 Human serum albumin, the most abundant protein in blood plasma, is physiologically important due to its unique ability of reversibly binding an extensive series of endogenous and exogenous compounds. Structurally, it is a nonglycoprotein composed of a single polypeptide chain subdivided in three homologous domains, which total 585 amino acids. To date, more than 50 genetic variants of albumin have been characterized at the protein and/or DNA level. The molecular distribution of these changes is clearly nonrandom, with clusters at the propeptide, N-terminus, and C-terminal regions of subdomains II B and III B. Moreover, population prevalences of these variants also present several interesting features. They are rare in most ethnic groups, but show some polymorphic variants especially in Amerindians (see Madison et al., 1994;Nielsen et al., 1997).The present report presents: a) a detailed review of the population distribution of albumin variants in South America, including new data in 5,020 individuals; b) a description of the molecular changes in three Brazilian variants; and c) a review of the physiological studies performed in four of these types, trying to integrate all of the results in a unified manner.
