Dehydrated Hereditary Stomatocytosis (Hereditary Xerocytosis)

Inheritance: autosomal dominant

Genes affected:

(1) PIEZO1: piezo type mechanosensitive ion channel component 1 at 16q24.3

(2) KCNN4: potassium calcium-activated channel subfamily N member 4 at 19q13.31

Clinical features:

(1) hemolytic anemia

(2) cholelithiasis

(3) hydrops and perinatal edema

(4) neonatal hepatitis with jaundice

(5) nontransfusional iron overload

(6) fatigue and exercise intolerance (associated with low intraerythrocytic 2,3-DPG concentrations and a left shift in the oxygen dissociation curve)

(7) hypercoagulability with postoperative thrombosis

(8) splenomegaly

Laboratory findings:

(1) elevated MCV and MCHC

(2) pseudohyperkalemia

(3) stomatocytosis with target cells in the peripheral blood smear