Biomedical subjects
Publications and source records attributed to D A Hahn.
A child with the Dyggve-Melchior-Clausen syndrome associated with elevated pipecolic acid levels in plasma and urine is described. Other studies of peroxisomal function, including phytanic acid, very long-chain fatty acids, and plasmalogen synthesis, were normal. This disorder may represent an incompletely characterized defect in peroxisomal metabolism.
We report a case of Fanconi's anemia with an extremely high proportion of fetal hemoglobin (Hb F). A three-year-old girl with multiple birth defects, mental retardation, and aplastic anemia consistent with Fanconi's anemia showed Hb AF by electrophoresis; the Kleihauer smear showed Hb F in 70% of her erythrocytes. Total Hb concentration was 34 g/L, mean corpuscular volume 119 fL. The proportion of Hb F was 45% by densitometry, 36% by radial immunodiffusion, and 30% by cation-exchange microchromatography. The Hb A2 was 0.5%; glycated Hb was 7.8% by affinity chromatography. Sample volume was insufficient for alkali denaturation. As exemplified with this patient, we recommend microchromatographic cation-exchange assay when Hb F exceeds 30% by densitometry. Here the effect of contamination by Hb A1 was lessened by the high proportion of Hb F. Cation-exchange microchromatography provides clinically relevant Hb F values more quickly than radial immunodiffusion and more conveniently than alkali denaturation.
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The glycated hemoglobin (GHb) is lowered by hemolytic anemia. The cation-exchange HbA1 has been shown to be lowered by hereditary spherocytosis (HS). The HbA1, however, can be increased by elevations of fetal hemoglobin (HbF). The affinity GHb, a parameter related to, but not identical with, the HbA1, and unaffected by HbF, has been shown to be low in hemoglobinopathies but not, to our knowledge, in HS and other non-hemoglobinopathic hemolytic anemias. Therefore, the affinity GHb and HbF was determined in four members of an HS family and in nine other cases of non-hemoglobinopathic hemolytic anemia, including three autoimmune hemolytic anemias, four red cell fragmentation syndromes (two "Waring blender" syndromes, one thrombotic thrombocytopenic purpura in association with tumor, and one case of disseminated intravascular coagulation), and two red cell membrane defects: paroxysmal nocturnal hemoglobinuria and another case of hereditary spherocytosis. The GHb for these nine cases was 3.6 +/- 1.7 percent (normal 6.0 +/- 2.0 percent; p less than 0.001). The reticulocyte count, available in four cases, was 0.23 +/- 0.14 and correlated negatively with the GHb. The average GHb in the HS family was 3.9 +/- 0.8 percent, which was significantly less than the normal of 6.0 +/- 2.0 percent (p less than 0.001); the HbF was less than 1.0 percent. It is concluded that the GHb is diminished in hemolytic anemias not associated with hemoglobinopathies and that this lowering reflects the shortened red cell life span in these processes. To our knowledge, this is the first report of low GHb in hemolytic anemia not associated with hemoglobinopathy, by the affinity chromatographic technique, as opposed to the cation-exchange chromatographic technique.