Hemoglobin H disease with hemoglobin Constant Spring in a child of Laotian extraction.

In alpha-thalassemia, deletion or inactivation of one, two, three, or all four alpha-genes causes, respectively, silent carrier state (-alpha/alpha alpha); alpha-thalassemia trait (--/alpha alpha in Orientals, and -alpha/-alpha in blacks); Hb H disease (--/-alpha); and Hb Bart's hydrops fetalis (--/--). We have described a case of Hb H disease with Hb Constant Spring (--/alpha alpha cs) in a Laotian child whose father had alpha-thalassemia trait and whose mother was a carrier of Hb CS, a mutant hemoglobin produced in minimal amounts. Since alpha-thalassemia is highly prevalent in Southeast Asia, physicians should become alert to the potential occurrence of Hb H disease and Hb Bart's hydrops fetalis in the new Oriental immigrants and their progeny.