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Blood, Vol. 113, Issue 6, 1350-1357, February 5, 2009
The monovalent cation leak in overhydrated stomatocytic red blood cells results from amino acid substitutions in the Rh-associated glycoprotein
Blood Bruce et al.
113: 1350
Supplemental materials for: Bruce et al
Files in this Data Supplement:
- Document 1. A new model of RhAG based on the Nitrosomonas europaea Rh50 crystal structure (PDF, 66.1 KB)
- Figure S1. Clinical details and biological parameters (JPG, 88.3 KB)
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A case study for the patient with OHSt “Nancy” has not previously been published. He was born in 1987 from hematologically normal parents, suggesting he is carrying a de novo mutation. Due to severe anemia, splenectomy was performed in 1994. The patient has been treated with acetylsalycilate ever since. Hemoglobin concentration was stable: 10–11 g/dL. Some chronic hemolysis associated with scleral and cutanaeous subicterus persisted. No liver enlargement was noted, however there was a microlithiasis. Blood sample was referred to us in 2003. The referral physician lost contact with the child after 2003. It is not known whether the patient developed post-splenectomy thrombo-embolic accidents despite his anti-coagulant treatment. (A) Red cell indices showed anemia (RBC: 3.28 1012/L; Hb: 11.5 g/dL), a hypochromia (25.60 g/dL), a pronounced macrocytosis (137.10 fL) and a high reticulocyte count (288.64 × 109/L; 8.8%). Stomatocytes (arrow) accounted for 10–20% of the red cells and were well formed. (B) Osmotic gradient ektacytometry was an unambiguous way to determine the type of stomatocytosis. (The maximum deformability index (DImax: normal: 0.41–0.53 (arbitrary units)) is the maximum value of the deformability index. The “hypo-osmotic point” (Omin: normal values: 143–163 mOsm/L) is the osmolality at which the deformability index reaches a minimum in the hypotonic region; it is the same as the osmolality at which 50% of the erythrocytes hemolyse in a standard osmotic resistance test. The “hyper-osmotic point” (O′: normal: 325–375 mOsm/L) is the osmolality in the hypertonic region (right leg of the curve) at which the deformability index reaches half its maximum value). In the patient (P), the pronounced right shift of the bell shape curve (DImax: 0.50; Omin: 215 mOsm/L: increase in the osmotic fragility; O′>450 mOsm/L: increase in the cell hydration) assessed the diagnosis of OHSt. C: control.
- Figure S2. Opening of the phe-gate (JPG, 65 KB)
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(A) View from the extracellular side. Helices are shown as Cα ribbon, side-chains of key residues are displayed and labeled. The side-chain of Phe225 in the postulated “open” position is shown in pink. (B) Close-up view of the central pore in one monomer of wild-type RhAG. The protein surface is colored gray, with darker areas representing either solvent accessible surface or cavities within the protein. Side-chains of key residues are shown and labeled. The side-chain of Phe225 in the postulated “open” position is shown in pink.
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