The occurrence of hemoglobin G (Coushatta) in the Louisiana Coushatta people

Preliminary data suggesting high rates of diabetes, its risk factors, and complications among the Louisiana Coushatta Indians were the impetus for developing the Pennington Coushatta Diabetes Study Program in 1993. We report on the occurrence of the variant hemoglobin G (Coushatta). This variant was first described in 1964 in the Alabama branch of the Coushatta in eastern Texas. Although the variant has subsequently been found sporadically in other locations around the world, its presence has not yet been confirmed in any other Native American group. Hemoglobin A1c is determined via the Diamet HPLC procedure. A variant hemoglobin is suspected when A1c is below the lower limit of normal (reference range 4.5-6.2%). Out of 90 individuals studied to date, 10 have A1c's below normal. Further characterization using the Beckman Paragon System with alkaline and acid gels in nine of these shows a band slower than Hb A but migrating with Hb S on alkaline gel and migrating with hemoglobin A on acid gel, indicating the probability of Hb G (Coushatta). The mean ± S.E.M. A1c was 2.9 ± 0.25% in these affected members. Eight of the individuals belonged to two nuclear families. Three of the individuals had diabetes. All affected members had normal hemograms. Given the high prevalence of diabetes in the tribe, it will be important in the near future to establish an alternate method of assessing long term glycemic control in diabetic members of the tribe.